Chan noted that the China Association for Science and Technology (Cast) was granted provisional status at the Washington Accord last year.

The accord is a global agreement among accreditation bodies for engineering qualifications.

"Cast's status will be reviewed in two years to see if it is qualified to become an official member," Chan, who stepped down recently as president of the 31,500-member Hong Kong Institution of Engineers, said.

The city needed up to 40 per cent more engineers than it now had, another veteran estimated.

At present, engineering graduates from mainland universities must do a master's degree of engineering in Hong Kong, typically for one year, and work for three years in the city before they are endorsed by the institution.

Chan said the master's degree was needed because the curriculum on the mainland was very different from that in Hong Kong.

If the international accord accepted Cast as an official signatory, mainland graduates could skip the further studies, although the three years of experience working in Hong Kong would still be mandatory, he said.

"Cast has been working with the educational authorities on the mainland to amend engineering curriculums at universities," he said, with more than 100 universities having modified their curriculums so far.

The accord has 17 official signatories, including engineering bodies from Hong Kong, Australia, the United States, Britain, Singapore and South Korea.

Chan Chi-ming, head of the Institute of Vocational Education's construction department, said the government should not press ahead with too many infrastructure projects at once, as the current demand for engineers was overwhelming. Chan estimated the local shortage at 30 to 40 per cent.

But he doubted the shortage could be eased if Cast became an official signatory to the accord, because the mainland itself had many projects and its engineers might prefer to stay put.

He said many engineers left the profession when Tung Chee-hwa and Donald Tsang Yam-kuen governed the city as chief executive, from 1997 to 2005 and from 2005 to 2012, respectively.

The exodus was due to the few infrastructure projects during those years, so "engineers were forced to leave the industry in order to make a living".

"Now the present government is pushing forward many projects, but we do not have enough engineers," he said.

Raymond Chan called for more students to be enrolled in studies for undergraduate and postgraduate degrees to fully tackle the shortage.

"About 360 students graduate as bachelors of engineering a year," he said. "That just cannot satisfy the demand for engineers these days."

In recent years, engineering companies had been competing to hire the talent they wanted, he said. "For some companies, the situation is like having lost 10 engineers but finding only six replacements."

A fresh graduate was paid HK$16,000 a month two years ago, but this year the starting pay was HK$18,000, he said.

"I have heard that an engineer with three to four years of experience wanted to quit to join another company," he said.

"His boss offered him a bonus of four months' pay and he still decided to leave."

If the supply situation was not improved, that could hinder the progress of projects, he said.

Big companies could afford to employ engineers from overseas and help them apply for work visas, but small and medium-sized companies would not have the resources to do so, he said.