Singapore Defence Minister Ng Eng Hen said on Friday that Indonesia has accepted Singapore's help to combat the haze that has haunted Indonesia and its neighbouring countries recently, China's Xinhua news agency reported.

Visible smog was seen in the air across the city-state this week, with the three-hour Pollutants Standard Index (PSI) hitting over 200 on Thursday night, the highest so far this year. A reading above 100 suggests that the air quality is "unhealthy," while a reading above 200 is "very unhealthy."

On Friday, air quality continued to stay in the unhealthy range, with the 24-hour PSI ranged from 140-160, according to the National Environment Agency.

The haze was largely a result of fire used to burn bushes in Sumatra so that the land can be utilised for agricultural purposes.

To deal with the issue, Singapore has registered its "deep concern " with the deteriorating haze situation to Indonesia, and has offered help earlier this week.

Ng said he had contacted Indonesia's Defence Minister on Thursday and Indonesia has accepted the offer.

"We've offered our Charlies (C-130s) for cloud seeding, and helicopters, Chinooks, for large water buckets to douse the fires in Sumatra," said Ng.

"Thankfully the winds shifted this morning and the haze has come down. We have to find some way of bringing down the problem and I'm glad the Indonesian authorities are looking at it."

According to Channel News Asia, Indonesia said on Friday it will also send more than 10,000 troops to fight the fire.