Restaurant worker Chia Yoke Kwai was forced by illness to leave her much-loved job, but when the option of part-time work arose, she jumped at the chance to get back into the workforce.

Madam Chia, 70, had already clocked up more than 20 years as a server at heritage Chinese eatery Spring Court Restaurant before retiring in 2012 to tackle her ill health.

When her old boss called her up in 2015 to ask if she could help out, she was more than happy to return on a part-time basis, where she works four-hour shifts about three days a week.

"Shorter hours now mean I have more freedom. I can go out, cook or do chores, or meet my sister to play mahjong," said Madam Chia.

"It's also good to work to stay active, and I can earn some money to travel," she added. She went to Taiwan last month with her daughter.

Spring Court director Mike Ho said the eatery started relying much more on part-timers about five years ago to cope with the manpower crunch.

"It's not easy to employ full-time staff to work at a Chinese restaurant; it's hard work and odd hours," he said.

"It's probably due to changing aspirations and lifestyle goals, as people's perception of what work should be changes and they want more flexibility."

Mr Ho's grandfather founded the restaurant in 1929 when it was called Wing Choon Yuen, and his mother, Madam Soon Puay Keow, is its managing director.

There are about 50 full-time staff, mainly managers, captains and some servers and kitchen staff, and about 30 part-timers, a mix of young and old working in service, kitchen and dish-washing roles, among others.

While the part-time arrangement helps the Chinatown restaurant cope with service needs, it is a lot more work for managers who have to do scheduling and deal with people not turning up for their shifts, said Mr Ho.

A new bonus scheme starting in October aims to incentivise part-timers by offering those who work at least four weekend shifts a month, and during peak periods, an additional 10 per cent of their pay after six months.

Spring Court general manager Raymond Ng said he hopes to secure "hard-core", experienced part-timers in this way. He also uses mobile apps to search for staff.

"If not, it's very hard to find workers. Youngsters would probably rather work in a cafe. So it's not a choice, it's a must," he said.