More problematic still is a long-term issue: how many of these children will stay and go to school, maybe even work here?

The mainland maternity issue is only a part of bigger demographic concerns.

Population problem

The government faces such issues because it is clueless in its population policies, says Philip Bowring, a Hong Kong-based journalist and commentator, in an opinion piece in the South China Morning Post.

He writes that immigration is one way to keep a population from ageing too quickly; more births are another way. Hong Kong's situation is in some ways unique.

Some people argue that the city needs its migrants because its birth rate is low, compared to other places in the world.

That indicates many Hong Kong couples are choosing to stay childless. Their reasons for doing so could include the high cost of housing, the lack of funds for nursery schools, or inadequate job protection for working mothers.

Bowring says the arrival of mainland babies was seen as a way to help ease the problem of the ageing population.

But one public figure disagrees.

'When the babies grow up and apply for their parents to come to Hong Kong, the impact on society will be serious,' says Miriam Lau Kin-yee, chairwoman of the Liberal Party. She says their elderly parents will further increase the ageing population.

If Hong Kong's population has more older people than younger people, government services may be overburdened and the workforce may not be as efficient.

Alleviating tensions

People who come here to work or start a new life face all sorts of difficulties. The city's traditions, culture and even Cantonese language may be foreign to them.

Some people say education may be a way to prevent problems caused by migrants' difficulties.

By allowing mainlanders' babies to stay and study, they can become assets to the city, not burdens, in the long run.

'The more that babies born in Hong Kong are educated here, the better,' writes Bowring.

He also thinks those children's parents should be allowed one-way permits to stay and take care of their young. A one-way permit is the permission to settle in Hong Kong and is obtained from mainland authorities.

According to law

A permanent solution to the mainland maternity issue may lie with Hong Kong's Basic Law.

Among the rules set out in Article 24, one defines permanent residents as 'Chinese citizens born in Hong Kong before or after the establishment of the Hong Kong SAR'.

The article also states that Hong Kong residents' children who are born outside the city are also entitled to the right of abode.

But in 1999, the Standing Committee of the National People's Congress in Beijing ruled that mainland-born children of Hong Kong residents do not have the right of abode.

That interpretation turned Hong Kong residency on its head.

The news

During a radio interview, Dr Cheung Wai-lun, the Hospital Authority's director of cluster services, said next year's quota for non-local pregnant women allowed into Hong Kong might be further lowered. The authority may even stop admitting them, he added.

This is good news for local mothers who are not getting enough pre-birth check-ups as a result of the heavy workload of medical staff. They often find themselves sleeping on beds lining the corridors of hospitals before giving birth. Many even go into labour without being attended to by doctors and nurses, who are facing personnel shortages.

Yet the new policy was not able to address the problem of heavily pregnant mainland mothers sneaking into the city at the last minute to give birth.

According to new rules, mainland women who are past their 28th week of pregnancy must provide proof of a hospital appointment before they are allowed to enter Hong Kong.

Last year immigration officers blocked the entry of 1,930 pregnant women, up from 1,634 in 2010.

Immigration Department director Eric Chan Kwok-ki said the department would notify mainland authorities of the names of pregnant women refused entry into Hong Kong. It will work with mainland authorities to take action against agencies that arrange for pregnant mainlanders to come to Hong Kong, as well as the owners of vehicles that carry them across the border.

Despite stepped-up efforts, it is not always easy to spot pregnant women trying to cross the border. The women are using various ways and means to cover up their pregnancies. Some wear baggy clothes in which they can pass undetected. In colder weather, they also wear overcoats and more layers of clothing.

The government has allocated HK$10 million in its latest budget to expand hospital services to help ease the influx of mainland mothers. A new storey will be built at the Fanling Maternal & Child Health Centre, which is considered a hot spot for mainland mothers.

More medical professionals will be employed at Maternal & Child Health Centres in Yau Ma Tei, Hung Hom, West Kowloon, and Lik Yuen in Sha Tin.

Facts and figures

The government has capped the number of mainland women allowed to have babies in the city at 34,400 (31,000 at private hospitals and 3,400 at public hospitals).

Yet the limit has had little effect on stopping mainlanders from coming to give birth in Hong Kong. Instead of maternity wards, many pregnant women simply go to emergency wards to give birth.

Here is a look at some figures to show how much strain mainland mothers are placing on local hospitals:

Last year, more than 1,600 women used emergency wards to give birth. That figure was almost double that of the year before.

There were 40 emergency births in November at the Prince of Wales Hospital alone.

At least 11 women reportedly gave birth in ambulances before arriving at North District Hospital in Sheung Shui, putting their own lives and those of their babies at risk.

Of the 800-odd women who gave birth using emergency services in 2010, a third left without paying. The charge for non-local women to give birth in public hospitals is HK$39,000 for those with a booking and $48,000 for those without.

According to the Hospital Authority's 2010/2011 annual report, HK$23 million of bad debt was recorded as a result of non-locals refusing to pay at public hospitals.

Last year, 19 obstetrics specialists left their jobs at public hospitals, shrinking staff numbers by 9.3 per cent. It was the highest turnover rate of any medical field in the past three years.

Voices: what people are saying

'These mothers, they have their own reasons for coming here. They might have local residents as husbands; they might have other children who would be disqualified under the reinterpretation of the law; they might be worried that they'll be forced to get an abortion in China; they might want special education for their children, Catholic, Protestant whatever. We can't judge them here in Hong Kong,' says Father Franco Mella, who is an active supporter of granting mainlanders the right to stay in Hong Kong.

'We can't be expected to look after everyone. There will always be a process for non-local people to become localised, but until then it's beyond the capability of any city to look after everyone who arrives. This is not about political expediency, not about populism, but the fight to maintain the power to make our own population policy,' says Albert Ho Chun-yan, the Democratic Party's chairman.

'Mainland women, other than those with Hong Kong husbands, should be banned from giving birth in the city's public hospitals. These mainland women do not help solve the problem of our ageing population. While their babies have permanent right of abode, we do not know when they will come to live in Hong Kong, which adds great uncertainty to our planning and quality assurance for such social services as education, housing and health care,' says chief executive hopeful Leung Chun-ying.