A report has revealed Indonesia is holding nine ships with more than 100 seafarers on board due to "illegal anchoring".

The Times of India cited Indian crew as saying the tankers and bulkers were detained four months ago in the Singapore Strait.

There are 87 Indian seafarers on five of the ships.

Most of the vessels were detained in the Singapore Strait on different dates in February for anchoring in what Indonesia claims to be its territorial waters.