Yesterday's action by 102 SMRT bus drivers brought into focus issues that have come with transport operators' growing dependence on foreign workers.
Bus operators began hiring bus drivers from China in 2008. They now make up 11 per cent of SBS Transit's pool of 5,300 drivers, and 22 per cent of SMRT's 2,000 drivers.
The pay gap between Chinese and Malaysian drivers was one catalyst for yesterday's protest. The former received much lower pay rises than the latter group, even though they perform roughly the same functions.
Veteran unionist and MP Halimah Yacob said this was probably because of SMRT's differing cost structures for the two groups of drivers.
For instance, SMRT has to pay for lodging for Chinese drivers, but not Malaysians, who typically commute to and from their homes across the Causeway.
She noted that the drivers should have sought proper avenues to address their grievances.
Even if they failed to reach a resolution with management, they could have turned to the Manpower Ministry, she said.
But Madam Halimah - who is also Minister of State for Social and Family Development - added that companies should be cognizant of changing circumstances facing Chinese workers.
"China is growing rapidly. Its economy is able to absorb many more workers, and they are also able to pay better than before," she said.
"So employers here have to factor that in."
Mr Kenneth Soh, a social worker at non-governmental organisation Transient Workers Count Too, said the larger issue may have to do with why there are not enough Singaporean drivers.
"Perhaps we need to relook at our salary policies, to attract more locals so as to have a lower reliance on foreigners," he said.
Active social commentator and former chief of union-backed insurer NTUC Income Tan Kin Lian also urged public transport operators to pay better salaries and provide better working conditions to recruit more locals.
"Locals will be more familiar with our roads and languages, and can interact better with commuters," he said.
Member of Parliament Cedric Foo, who chairs the Government Parliamentary Committee for Transport, said buses were an essential public service, and Singapore must guard against situations where such service providers are held hostage to protesters.
"There is always a balance to be struck between employee and employer interests," Mr Foo said.
"But conflicts do surface from time to time, and due process should be followed to address them.
"(Commuters) should not be penalised for this."