The Meteorological Department has issued a warning on haze-induced low visibility of less than five kilometres over the waters off nine states today.

It said in a statement that the affected areas are Kedah, Penang, Perak, Selangor, Negeri Sembilan, Melaka, Johor, Pahang and Sarawak.

"The condition is risky to sea vessels without navigational equipment," it said.

The department also said thunderstorms over the waters off Kuching, Rejang, Mukah, Miri and Bintulu in Sarawak are expected to persist this morning.

It said the accompanying strong winds of up to 50 kmph and high waves of up to 3.5 metres are dangerous to small boats.