Malaysian authorities said on Wednesday they had saved 70 illegal Indonesian immigrants from a ship that was in danger of sinking as its passengers tried to sneak back into Indonesia.

The rickety vessel had left from an illegal jetty in Selangor when it was spotted by authorities, a Malaysian maritime official told AFP .

"We found one suspicious boat with no lights, nothing, and when we went closer they tried to get away from us, but after 10 minutes we managed to stop them," Southern Region Commander Che Hassan Jusoh said.

He added 70 illegal Indonesian immigrants were found aboard the cramped vessel, which he said was not seaworthy, was badly overloaded and was taking on water.

He said there were six children on board, all of whom were aged under three.

Group taken to detention centre

Authorities have placed the group in a state immigration detention centre while further investigations are carried out, he said.

There were nearly two million Indonesian workers in Malaysia including 800,000 illegals as of February this year, according to the Indonesian embassy.

Malaysian Prime Minister Najib Razak said recently his country was being used as a transit point for illegal immigrants.

The most recent incident follows the drowning of more than 12 suspected illegal immigrants off Malaysia's southern coast in the last two months.