[12] In the 1968 general elections, Sia, under the alias of Chia Seong, was among the three trade unionists fielded by the People's Action Party (PAP) in the constituency of Moulmein.

[13] The other two unionists were Eric Cheong and Seah Mui Kok, representing Toa Payoh and Bukit Ho Swee respectively.

[15] In 1970, the Malaysia-Singapore Airlines (MSA) allegedly adopted a policy to prefer hiring white expatriates than locals with similar or better qualifications.

As a member of the central committee of the National Trades Union Congress (NTUC), Sia called out MSA in Parliament, saying such nefarious policies have created dissatisfaction and lowered morale among locals, and warned that the Government's liberal policy of inviting qualified expatriates had been abused by certain industries.

[16] Sia elaborated in his speech on 19 March 1970: The Singapore Air Transport Workers' Union has over the years battled strenuously for a concrete plan for nationalisation and a training programme for suitably qualified national staff to be groomed to replace expatriates.

[17][18] In March 1971, during a debate on budget proposals, Sia suggested three amendments to the Employment Act, namely to reduce the maximum duration of collective agreements in pioneering industries from five years to three years, raise the maximum limit for bonus negotiations from one month's salary to a more realistic sum, and raise employers' Central Provident Fund contributions.

[19] In August 1971, Sia called out the International Chamber of Commerce and the Singapore Employers' Federation for their "lukewarm response" towards the Government's plan to establish a national wage council.

[22][23] With the union present membership at 3,900, Sia announced an initiative to unionise about 12,000 English language teachers, and released a 10-point plan to improve teaching conditions.

Sia also felt that duty levied on cultural entertainment, such as concerts and movies, posed an "unnecessary burden" towards businesses, organisers and attendees.

[37] Sia elaborated in Parliament: He has done the unexpected this year by decreasing income tax rates for the benefit of the taxpayers to the tune of S$53.9 million.

Let us hope that this propitious time is not too far away.Coming back to his tax measures, Mr Speaker, Sir, allow me to make certain observations in regard to the Finance Minister's proposal to increase the rate of entertainment duty.

But to impose an additional duty on admission charges for cultural entertainment, such as stage plays, concerts, music performances and dances, etc.

In Sia's opinion, the shortage could be solved by making teaching spiritually and financially attractive career, through a revision of salary and promotion for teachers.

[47] In early 1991, Sia approached Prime Minister Goh Chok Tong and broached the issue of retiring from politics.

Goh described Sia as an "unselfish man who know the pain of stepping down as a PAP MP", and was proud of his decision to make way for new candidates.

[53] In 1997, the Singapore education system started to change into an ability-driven one after Prime Minister Goh Chok Tong outlined his "Thinking Schools, Learning Nations" vision.

[56] In response, Minister for Education Teo Chee Hean that problems associated with the introduction of new programmes were inevitable, and surveys conducted by the ministry suggested that teachers were adaptable and able to overcome any issues.

However, Tan Kin Lian, chief executive officer of NTUC Income, said that the funds in the account were not due to STU.

STU also withdrew all prior statements and allegations that suggested the contrary, and decided to give Sia an award recognising his contributions to the union.