The actions taken against the Chinese SMRT bus drivers for their role in a two-day strike are not a bilateral issue between China and Singapore, Acting Manpower Minister Tan Chuan-Jin said yesterday.

"This is an issue where laws are violated; in this case, the SMRT bus drivers overstepped the boundaries," he said.

"They broke the law by participating in an illegal strike. It's important not to politicise the issue."

He made the comment when asked whether the actions against the bus drivers would affect Singapore's relations with China.

Four of them have been charged with instigating work stoppage; another will be charged tomorrow, and 29 are being repatriated. The others will be given police warnings for their role in disrupting an essential service.

At a press conference yesterday, Mr Tan said that foreigners must abide by the laws of the land. The Government will take firm action against any illegal strikes, regardless of the strikers' nationality.

As with all incidents involving foreigners, the protocol is to work with their embassies, and the Government has been working very closely with the Chinese Embassy.

"We will have to let the law unfold and take the necessary action. We have made that quite clear to the embassy and they understand that," Mr Tan said.

In a statement last night, the Chinese Embassy said it was in contact with the authorities. It added that it "has expressed deep concern over this incident several times, has reasonable worries over the development and effects of the current situation, and hopes that the relevant Singapore authorities will handle this matter appropriately".

The chief of the Government Parliamentary Committee for Defence and Foreign Affairs, Dr Lim Wee Kiak, did not think the episode would affect ties adversely.

"Our laws must be respected," he said. "We have labour dispute mechanisms in place, even for foreign workers in Singapore. They must have access to these labour dispute mechanisms."

Maria Almenoar

Additional reporting by Tham Yuen-C