Singapore will issue preventive measure notices under the Transboundary Haze Pollution Act (THPA) to seven companies in Indonesia suspected of involvement in forest fires that have contributed to worsening haze, said Sustainability and Environment Minister Grace Fu.

She said the notices would be issued by the National Environment Agency (NEA), following investigations into errant companies found responsible for causing transboundary haze in Singapore.

"Our investigation so far suggested that some of the haze experienced in Singapore originated from fires on the lands of seven companies in Indonesia.

"Where warranted, we will take further action under the THPA based on the information and evidence available," she said in a press conference today.