Singapore will deport 29 mainland Chinese bus drivers and pursue criminal charges against five others for involvement in the city-state's first strike since the 1980s, the government said Saturday.

"Foreign nationals should abide by the laws of their host countries. Singaporeans who work and live overseas are also expected to do so. Laws must be upheld," Manpower Minister Tan Chuan-Jin told a news conference.

The two-day strike, which caught the government by surprise, has highlighted tightly-controlled Singapore's heavy dependency on migrant labour to drive its economic growth amid a labour shortage resulting from falling birth rates.

The manpower ministry said 29 drivers' work permits had been revoked and immigration officials will be repatriating them for involvement in the work stoppage, which the government has declared illegal.

While underscoring that the Chinese workers broke the law, Tan also chided their state-linked employer, transport group SMRT, saying it "could have done better in managing their labour grievances and concerns".

A fifth driver has been arrested and will be charged in addition to four others who have been brought to court for allegedly instigating the November 26-27 strike.

If found guilty of involvement in an illegal strike, they could be jailed for up to a year or fined a maximum of Sg$2,000 ($1,640) -- the equivalent of two months' wages -- or receive both punishments.

Strikes are illegal in Singapore for workers in "essential services" such as transport unless they give 14 days' prior notice and meet other requirements.

The Chinese government has urged Singapore to respect the workers' legal rights while also cautioning its citizens to obey local laws.

The Chinese embassy said it was "very much concerned" about the arrests and had made consular visits to the drivers, the Xinhua news agency reported.

A total of 171 drivers launched the strike by refusing to report for work and staying in their dormitories, with the number falling to 88 on the second day.

They were questioning why they were being paid less than their Malaysian counterparts.

SMRT has had to hire bus drivers from China and Malaysia due to a chronic labour shortage.

About a third of Singapore's population of 5.3 million are foreigners, causing friction in recent years as disgruntled Singaporeans accuse them of causing overcrowding, straining housing and public services and stealing jobs.

Singapore's last strike took place at a shipyard in 1986.

Unions have since cooperated with the government and private employers in a tripartite system to protect industrial harmony, attract foreign investment and negotiate wage increases and other benefits.

An SMRT spokesman told AFP that 22 percent of its 2,030 bus drivers were from China, another 22 percent from Malaysia and the rest Singaporean citizens and permanent residents.

The strikers drew sympathy from some Singaporeans after their work and living conditions were exposed by the walkout.

SMRT has promised to look into the strikers' demands, fumigate their bedbug-infested dormitory rooms, find alternative housing in 2013 and open permanent communication lines with its Chinese workers.

Sinapan Samydorai, director for Southeast Asian affairs at civil rights group Think Centre, criticised the government action as "a bit too harsh" and told AFP the drivers should have been let off with a stern warning as their grievances were real.

The opposition Workers' Party also issued a statement calling for fair treatment of foreign labourers.