SINGAPORE - Southeast Asian environment ministers will meet in Singapore on Friday to discuss ways to help Indonesia extinguish forest and brush fires causing a thick smog blanketing the region.

Singapore's government said in a statement that its environment minister, Yaacob Ibrahim, has invited his counterparts from Brunei, Indonesia, Malaysia and Thailand to the city-state to help Indonesia douse the fires.

"The meeting will discuss urgent and long-term measures that the countries could undertake to tackle the regional haze problem," it said.

In a separate statement on Wednesday, Singapore's ministry of foreign affairs said Prime Minister Lee Hsien Loong has written to Indonesian President Susilo Bambang Yudhoyono to "express his disappointment over the recurring haze problem".

"Mr. Lee had also noted that while it may be too late this year to prevent the fires that cause the haze, it was critical to take action now in order to prevent future forest fires," the statement said.

Forest fires are burning mainly in Indonesia's part of Borneo island and on Sumatra island, also in Indonesia. Most are deliberately lit. Each dry season, forest is illegally torched to clear land for agriculture, blanketing Southeast Asia in smog.

But farmers are also using traditional slash-and-burn methods to clear or rejuvenate land.