About 60 Chinese bus drivers in Singapore stayed off work on Tuesday, the second day of a rare labor stoppage in the city-state.

State-linked transport firm SMRT said 60 of the 102 bus drivers who refused to work on Monday also did not show up on Tuesday despite an agreement to do so.

"Some 60 did not turn up for work in the morning, some of whom have valid medical reasons," SMRT said in a statement.

"We continue to keep our communications open ... and are also working with the relevant authorities to find an amicable resolution."

The Chinese drivers on Monday refused to board a shuttle bus from their dormitory to a nearby depot.

One of them, who declined to be named, said they felt aggrieved over a disparity in pay between Chinese and Malaysian bus drivers.

After talks with SMRT management, with police on standby, the drivers said they would report for work on Tuesday.

Local media said they were absent because the Malaysian drivers recently received a pay rise of 275 Singapore dollars ($225) and one month bonus pay, while the Chinese drivers received only an increase of 75 Singapore dollars without a bonus.

SMRT said on Monday that the bus drivers had agreed to return to work after the company promised to consider their demands for pay equal to other foreign drivers and give them an answer in about one week.

SMRT said that some of the bus services were affected and other drivers were called to help.

Local daily Lianhe Zaobao said that by noon on Tuesday another 10 drivers had returned to work and other drivers said they would return to work on Wednesday.

SMRT insisted that it has had sound lines of communication.

A human resources executive at SMRT, which operates about 25 percent of the bus services in Singapore, was called in to resolve the dispute on Monday. The police was called in when the talks came to a standstill, but they did not interfere as there were orders not to do so.

News of the no-show incident became a hot topic on social media. Singapore has had few no-shows or strikes over the past few decades as the authorities put in place rules and measures that discourage strikes while trying to protect the employees' rights through consultations that involve the workers, the employers and the government.

The labor movement works closely with the government and private business, making the city-state an attractive place for foreign investment.

The last strike in Singapore was in 1986, local media said.

SMRT is 54 percent owned by state investment firm Temasek Holdings. Singapore has been hiring bus drivers from China and Malaysia because of a chronic shortage of manpower.

The Ministry of Manpower on Monday issued a stern warning to the drivers, saying it "takes the workers' actions very seriously" and was closely monitoring the situation.

AFP-Xinhua