There Ho joins some 40 other passengers, all wearing stickers on their chests displaying their destinations and the time for boarding. Meanwhile, the staff of different bus or limousine companies shout out the destination for the next bus or van to leave and urge the respective passengers to step forward.

It is a practice which the frequent travellers are so familiar with that everybody is at ease despite the milling crowd and shouted instructions.

The schedules of the shuttle buses or cars are fluid. When a passenger buys a ticket the shuttle company undertakes to let the passenger board within 30 minutes, while staff will try to group passengers with the same or nearby destinations into a car.

If Ho were to take a direct flight from Kaohsiung to Shenzhen, it would take four hours in total transit time. However, he says air fares of direct flights are too high and flights too infrequent, so he sticks to using Hong Kong as a transit - a common reason given by the other 60 per cent of Taiwanese businessmen in the Pearl River Delta who continue to go through Hong Kong at present.

There are only two weekly services between Kaohsiung and Shenzhen, compared with at least nine daily flights between Hong Kong and Kaohsiung, which offer flexible travel plans for passengers. This is in contrast to direct flight service where passengers have to confirm their tickets two weeks in advance.

But this does not mean that flights offered by Cathay Pacific Airways or Dragonair will be safe from competition forever. Once the direct flight service increases to a critical level, Taiwanese passengers will skip Hong Kong.

'I will switch to direct flights one day when the air service between Kaohsiung and Shenzhen is upgraded to one flight every two days from one flight per week at present,' Ho said.

The long and unpredictable queueing time at the border line controls between Hong Kong and mainland are a nightmare for passengers.

'I've been kept waiting for nearly an hour in a van when we were queueing at the immigration on the mainland side,' said Betty Yung who has run a factory in Dongguan for 18 years.

The experience made her switch to direct flights. 'I can save at least two hours per trip by flying to Shenzhen from Taipei,' she says.

Cross-border transportation services come in two forms. Passengers can choose a deluxe service and travel in a seven-person van which costs at least HK$150 per trip; or go for a more down-to-earth service by taking a coach which costs as little as HK$40.

Yung said she prefers the deluxe version as she does not need to get out of the car for immigration checks which is troublesome when she is travelling with luggage.

In a worst-case scenario, however, all passengers in a van will be held by mainland immigration officials if just one passenger has an overdue visa, even though the passengers do not travel in group, said a cross-border driver.

'That's why I will check up the passport of each passenger before I take off.' Another source of irritation to commuters is that up to half of the driving lanes through the checkpoints are often closed.

Most of the Taiwanese who still go through Hong Kong to travel to mainland said that they will stick with using Hong Kong as a transit until cross-border immigration procedures are streamlined.

Border bottleneck

Commuters say they want border controls to be streamlined

The proportion of Taiwanese business commuters to the mainland who fly through Hong Kong: 60%