Australian Prime Minister Tony Abbott refused again Sunday to deny allegations an official paid thousands of dollars to turn back a boatload of asylum-seekers, despite calls from Indonesia for answers.

The claims -- that the captain and five crew of the boat were each paid US$5,000 by an Australian immigration official to turn back to Indonesia -- were made to Indonesian police on Rote island in the country's east.

The row risks damaging already strained relations. Australia's ambassador to Indonesia Paul Grigson resumed his post last week after being recalled over the April execution of two Australians for drug-smuggling.

Abbott said the key message for Indonesia as well as Australian voters was that his government was "prepared to do what's necessary" to stop people-smugglers from transporting asylum-seekers by boat to Australia.

"I think it's very important that the Australian public are reassured that there is a government in charge which will not waver for a second in our determination to ensure that the boats stay stopped," he told reporters.

"And it's very important that the Indonesians know that the Australian government is absolutely resolute in our determination never to see this evil (people-smuggling) trade start up again."

Abbott said keeping the boats stopped was good for both countries and had helped prevent asylum-seekers from risking their lives on treacherous sea journeys.

"We will do whatever is reasonably necessary, consistent with the principles of a decent and humane society, to keep the boats stopped," he added.

Greens senator Larissa Waters said her party would move in the upper house Senate on Monday for an order "for a production of documents to try to get to the bottom of whether money has changed hands, potentially illegally".

Indonesia's foreign ministry spokesman Arrmanatha Nasir said Saturday Jakarta was seeking clarification from its neighbour and the payments, if true, "will be a new low for the way that the Australian government is handling this issue".

A spokesman for the UN refugee agency, James Lynch, told the British Broadcasting Corporation Friday that UNHCR staff interviewed the 65 passengers on board "and they have said that the crew received a payment".

The asylum-seekers -- from Bangladesh, Myanmar and Sri Lanka -- arrived on Rote island in late May after being intercepted by the Australian navy en route to New Zealand.

Abbott's conservative coalition implemented a tough immigration policy after coming into power in September 2013 that included military-led efforts to turn back such boats, which mostly come from Indonesia.

The hardline policy also involves sending asylum-seekers that arrive by boat to camps on the Pacific islands of Nauru and Papua New Guinea despite strong criticism from rights groups.

They are banned from settling in Australia even if found to be genuine refugees.

Only one boat with asylum-seekers has reached the Australian mainland since December 2013. Before the policy was introduced, boats were arriving almost daily, with hundreds drowning en route.