SINGAPORE - One of the Chinese bus drivers involved in a recent strike was sentenced to six weeks in jail in Singapore on Monday, while four others await trials scheduled for Thursday.

Twenty-nine others were deported to China on Sunday.

Some 171 Chinese bus drivers stayed away from work on November 26 in protest against unequitable pay increases and allegedly discrimination of local public transport operator SMRT. 88 of them failed to return to work the following day.

Bao Fengshan, who was not represented by a lawyer, pleaded guilty to the charge for his role in the rare strike on Monday. The prosecution has asked the court to sentence him to six weeks in prison, saying that Bao was "far from a mere passive participant" and had been uncooperative.

Each of the four other drivers arrested faces a charge of instigating an illegal strike, while He Junling, one of the drivers, faces an additional charge of inciting an illegal strike with online message he posted.

If convicted, the drivers will face a fine of up to 2,000 Singapore dollars ($1,639), or maximum imprisonment of 12 months, or both on each charge.

Singapore government has reiterated its policy of "zero tolerance for illegal strikes," and Acting Manpower Minister Tan Chuan-Jin has described the drivers' action as an illegal strike shortly after the incident. The Ministry of Manpower said the actions of the drivers "disrupted an essential service and Singapore's industrial harmony."

The Chinese workers had complained of unequal pay rises as they received a pay rise of 75 Singapore dollars, while the company's Malaysian drivers received pay rises of 275 Singapore dollars, in addition to a difference in bonus.

He Junling, who posted a message on the Chinese website baidu.com, also complained that the company had been using a change from six work days to five to cut the pay for overtime work. Another driver said the Chinese drivers could now earn only about 1,400 Singapore dollars, compared with 2,000 Singapore dollars earlier.

Documents also showed the company insensitively used the phrase "excluding Chinese service leaders" in several places in a written notice, referring to the drivers.

SMRT has insisted that door of communication were open but the drivers said they had not been able to get their voices heard. A senior management of SMRT said she has heard of the grievances of the Chinese workers but had received no written complaint. The chief executive officer of the company was taking a leave overseas and showed up at the workers' dormitory for the first time on Friday, two days after the arrests were made.

The Chinese Embassy in Singapore said it has conveyed its concerns to the Singapore authorities many times and had made consular visits to the drivers.

SMRT is a government-linked public transport operator providing 25 percent of the bus services in Singapore. It also operates most of the mass rapid transit systems, which has experienced several major disruptions over the past year or so.

Industrial actions have been rare in Singapore over the past decades as the authorities put in place measures that allow consultations involving the workers, the employers and the government, while at the same time putting in place legal rules that make it as difficult as it can be to have a legal strike.

Under Singapore law, workers in essential services such as transport and public utilities must give their employer at least 14 days' advance notice of their intention to have a strike. The notice has to be signed by at least seven fellow workers involved in the strike or by at least seven union representatives of the workers. The notice then needs to be acknowledged and signed by the employer, after which, that notice needs to be put up in at least three conspicuous places where the workers are employed.