While being the Minister for Social Affairs, Mr Othman Wok was also an officer cadet in the fledgling People's Defence Force (PDF).

But he did not receive any special treatment, recalled 70-year-old Tien Chao Heng yesterday.

"It was an inspiration to all of us, because here was someone who was a minister that was getting the same tongue-lashing and shouting as us," he said.

Mr Tien was an officer cadet with Mr Othman in the 1960s, when both men volunteered to serve in the PDF, a corps of volunteer soldiers that would train on weekends.

The pioneer Cabinet minister, who died on Monday aged 92, was 41 when he joined the PDF.

After his memorial service yesterday, Mr Tien and other volunteers recounted their time in military service with one of the nation's founding fathers.

Mr Othman was a man who, despite his political stature, was respectful and humble and loved to crack jokes, they said. "He never talked down to people... he behaved like he was one of us," said Mr Tien.

The men gave nicknames to one another, and Mr Othman's was "Ozzy".

A former MP for Pasir Panjang, Mr Abbas Abu Amin, said Mr Othman always respected officers with a higher rank. Mr Abbas held the rank of major in the PDF and he said Mr Othman, then a captain, always saluted him first. "We all thought that no matter how high your rank was in the army, you should always respect a minister, but the moment (Mr Othman) is in uniform, he would be respecting you as a senior officer," said Mr Abbas.

Mr Tien said that in those early days, the camaraderie among the men was high. They would joke with one another to soften the blow of tough training in the jungle and the "not-so-palatable" food.

"If someone asked how the food was, we would say 'the chilli sauce was nice' or 'the light sauce was delicious'," said Mr Tien with a chuckle.

In his eulogy yesterday, Prime Minister Lee Hsien Loong paid tribute to Mr Othman for volunteering with the PDF at a time when the country "urgently needed to build up the Singapore Armed Forces".

Other pioneer ministers who were also in the volunteer force included Mr Ong Pang Boon, now 88, and Mr Jek Yeun Thong, now 86.

Mr Othman would go on to march in the first National Day Parade in 1966 as an officer cadet, and then as a lieutenant leading the PDF contingent the following year.

"Othman was one of several ministers who volunteered, to set an example and underline the importance of defence," said Mr Lee.