Foreign Minister K. Shanmugam said on Sunday that he will ask for a clarification on the "contradictory signals" from the Indonesian government regarding the list of Singapore-linked companies which apparently use fire to clear land.

He said Environment Minister Vivian Balakrishnan was told that there were no companies with any Singapore linkage. But Indonesia named two Singapore companies as among those responsible for the fires.

"We need clear clarification, and a clear statement from Indonesia, together with evidence," he said.

He was speaking to reporters before distributing masks to residents living in studio flats in his Chong Pang ward.

The land-clearing method is seen as a key cause of the haze crisis now engulfing Singapore and Malaysia.

Mr Shanmugam, who is also Law Minister, said that the haze would cause an "image impact," where people would associate Singapore with haze during this period. An example he gave of impact is three senior American statesmen in their 80s who cancelled a conference to be held here on Tuesday due to the haze.