Updated

Indonesia's Foreign Ministry says it's "very concerned" by claims that Australian officials paid the crew of a migrant boat to return to Indonesian waters.

Police in Indonesia's East Nusa Tenggara province say the boat's captain and five crew members detained on remote Rote island claim they were each paid $5,000 after being intercepted by an Australian navy ship.

Foreign Ministry spokesman Arrmanatha Nasir said the Indonesian government is concerned that if such payments are happening they could encourage human trafficking.

Police say the boat was carrying 65 migrants, mostly from Sri Lanka and Bangladesh.

Australia's Immigration Minister Peter Dutton said the department doesn't comment on operational matters.

Australia has a policy of turning back and refusing to resettle any refugee who arrives on its shores by boat.