FOUR years ago, Mr Baey Ee-Qiang graduated from the National University of Singapore with a degree in electrical engineering.

But instead of becoming an engineer or researcher, the Singaporean chose to become a bank executive - partly due to the higher pay. "About half of my friends who studied engineering ended up doing something completely different," said the 28-year-old.

Between 2008 and 2011, the number of citizens and permanent residents in Singapore's science industry fell by 200, according to the latest annual national surveys.

But the number of foreign researchers, engineers, technicians and support staff shot up by 4,551 in the same period. By 2011, foreigners made up 30 per cent of the science industry ranks, up from 22 per cent in 2008.

This is despite at least 20,000 people per year graduating with science and engineering degrees and diplomas in recent years.

The Education Ministry would only say that the "majority" of science and engineering graduates are citizens and PRs.

Singapore is not unique in this respect. A report in science journal Nature Biotechnology last December found many countries have high numbers of foreign scientists. Switzerland, Canada, Australia, the United States, Sweden and Britain had proportions of foreign scientists ranging from 33 to 57 per cent.

Many laboratories strive for a mix of nationalities to foster new perspectives and ideas, scientists told The Straits Times.

Mr George Musser, an editor at the Scientific American magazine, said: "A large foreign-born population of scientists is the mark of a cosmopolitan society and speaks well of Singapore.

"It also has side benefits like making the country a livelier place to live and providing top-notch teachers for local students."

However, he added: "A nation does have certain obligations to its own people which can cause tension with the commitment to hiring foreign-born scientists.

"It is hard to motivate young people to study science when the job market is so competitive."

Dr Gene Yeo, 36, a Singaporean specialising in genomics and neurological diseases, added that Singaporeans should make up the backbone of the local industry.

He said: "The danger of not having enough local talent is that we become overly reliant on others to 'cut your grass and feed your children'. When times in other places or in their own countries are better, foreigners will go."

Tertiary institutes and companies - which accounted for the bulk of the rise in foreigners - said Singapore's own talent pool is too small for their needs.

At Nanyang Technological University, most research staff are hired on a project basis, with contracts ranging from a few months to three years.

"Expanding our search beyond Singapore will increase our chances of recruiting talents who are agreeable to these employment terms," said associate provost for faculty affairs Angela Goh.

In recent years, the Government has helped to set up research centres and speeded up its work by hiring top global minds.

Some scientists said Singaporeans may be deterred by the long hours and high risk of failure in science, whereas foreigners may see coming here as an opportunity to change their lives.

Local graduates may also have been wrongfooted in recent years as Singapore ventured into new fields, others suggested.

A spokesman for Rolls-Royce, which opened an advanced technology centre here last year, said it has been "challenging" to hire Singaporeans and PRs in fields such as electrical power engineering and data analytics.

Of the centre's 42 scientists, 37 are Singaporeans or PRs. The firm has brought in employees from other countries to train locals.

"The type of research and high-value manufacturing work we do (at the centre)... is new to Singapore," said the spokesman.

At the Novartis Institute for Tropical Diseases, 25 of the 86 full-time research associates were foreigners as of January.

A spokesman said the company has difficulty hiring locals in fields related to industry drug discovery, such as medicinal chemistry and pharmacology.

The drive to attract brand- name companies to set up shop in Singapore has also led to a squeeze on specific talent.

"We face additional competition for data analytics professionals from technology companies such as Google, Apple, IBM and other multinational companies," said the Rolls-Royce spokesman.

Not all scientists are worried. Some pointed out that importing foreigners to build up new fields will ultimately lead to jobs for Singaporeans. This has been the case since Singapore brought in renowned scientists a decade ago to develop its biomedical muscle.

Local institutes have also rolled out measures to give Singaporeans the required skills and to persuade them to join the science industry.

The Singapore Institute of Technology will start a two-year degree course this year for diploma holders who want to be power engineers.

The national Agency for Science, Technology and Research (A*Star) has given out more than 1,100 scholarships for Singaporeans to pursue doctorates. Of them, more than 350 have completed their studies and are now working at the agency or in academia, hospitals and industry.

But other observers said Singapore should keep an eye on the balance between foreigners and locals in its science industry.

Some said citizens and PRs should make up at least half of the industry ranks and 80 per cent of the graduate students in laboratories.

More can also be done to encourage local firms to invest in research, which could create jobs for Singaporeans, they added.

Foreign firms have consistently been the largest contributors to Singapore's research and development landscape.

In 2011, they spent $3.5 billion - more than triple the $1.1 billion local firms pumped in and almost half of all spending.

In contrast, spending by Singapore companies grew by a more modest 14 per cent from $985 million in 2002.

In the meantime, Singapore should draw its foreign talent from different countries and not one dominant source, said former A*Star chairman Philip Yeo, who now heads enterprise development agency Spring Singapore.

"This will make Singapore internationally broad and rich in talent," he said. "Diversity is strength."