An asylum-seeker vessel purportedly heading for New Zealand was intercepted by Australian officials who reportedly spoke to the captain. What happened after that has sparked many cautious responses from Australian ministers

The Australian government is facing growing pressure to respond to allegations that it paid people smugglers to return an asylum-seeker vessel back to Indonesia.

The prime minister, Tony Abbott, refused to rule out whether such an operation had occurred, but said the government was “prepared to do what is necessary” to prevent asylum-seeker boats arriving in Australia.

The claims have arisen gradually, and information from official sources remains sparse. Here’s what we know so far.

How did the allegations emerge?

The allegation that people smugglers were paid by Australian officials during an operation to turn back an asylum-seeker boat emerged in a Radio New Zealand report on 8 June.

A Bangladeshi asylum seeker, Nazmul Hassan, who was on board the vessel spoke from inside an Indonesian detention centre. He said the vessel was intercepted by Australian authorities in May. The vessel was purportedly bound for New Zealand. This turnback operation had been reported in May by the West Australian.

Facebook Twitter Pinterest An Australian navy vessel shadows a boat believed to be carrying asylum seekers off Indonesia. Photograph: BASARNAS/AFP/Getty Images

Hassan told Radio New Zealand the vessel was intercepted twice by Australian authorities. During the first interception they were warned to turn back by Australian authorities and were asked not to attempt to continue to New Zealand. Five days later they were again intercepted and Australian officials on board asked to speak to the captain of the vessel.

On asylum-seeker vessels the captain and crew are often paid by the people-smuggling syndicates to undertake the ventures. They are paid substantial amounts of money because of the risk they could be arrested and charged upon entry to Australia with people-smuggling offences.

Hassan said that during this second interception the captain and crew were paid A$7,200 for each passenger if they returned to Indonesia.

“What they told the chief captain I don’t know. But after he came back, he called another five captains and say that Australia wanted to donate for us to go back to Indonesia,” he told Radio New Zealand.

A letter was also published that was signed by 65 of the asylum seekers on board the vessel.

It said: “Then they [illegible] our six sailors and donated them by giving at least 7,200 (ASU) dollars per person. They never ask to us any opinions and they also never acept our petition.

“Then they take away our better boat and give two small boats. That boat had just a little days foods like biscits and chock lats. And they also give very little fuel just 200 litters for 4 to 5 hours journey. Then they [illegible] our boats and they leave us near Indonesian land. After that our captain drive our boats one hour later one boat fuel finished. We all jump to another small boat.”

It said the boat later smashed up on rocks and the asylum seekers were forced to swim to shore.

On 10 June Fairfax Media published similar claims from a police officer on Rote island. He said the captain of the asylum-seeker vessel, Yohanes, had told him that each of the six crew members received US$5,000 from the Australian officials.

Subsequently, the United Nations high commissioner for refugees (UNHCR) also said it had interviewed the asylum seekers on board the vessel, who reiterated their claims.

On Monday, as reports of the claims continued, a Daily Telegraph reporter with close ties to the prime minister’s office reported suggestions that Australia’s foreign intelligence agency, Asis, may have engaged in a “disruption” operation that involved payments to people smugglers.

To date these remain the main sources for the allegations about the payments.

What have the responses been from the Australian government?

The responses from senior ministers in the federal government were initially dismissive. When the foreign minister, Julie Bishop, and the immigration minister, Peter Dutton, were asked whether payments were made to people smugglers, both replied “no”.

However, Abbott took a more circumspect approach and refused to deny the claims.

Instead he told 3AW radio last week: “There are all sorts of things that our security agencies do that they need to do to protect our country and many of those things just should never be discussed in public. Operational matters, when it comes to national security, are never discussed in public and that’s the way it should be.”

Despite the initial responses from Dutton and Bishop, other minister have also responded cautiously. On Monday the former immigration minister, Scott Morrison, was asked whether people smugglers were ever paid while he was overseeing the portfolio.

Facebook Twitter Pinterest Scott Morrison has refused to discuss operational matters. Photograph: Mike Bowers for the Guardian

He said in response: “Operational matters are not things that we canvass for very good reason.”

When asked whether it would be a problem to pay people smugglers, he said: “This government had a responsibility for stopping the boats, and that’s what we’ve done.”

How have Australian opposition parties responded?

The Labor immigration spokesman, Richard Marles, has written to the auditor general, Grant Hehir, asking him to investigate the allegations surrounding the payments. The Greens senator Sarah Hanson-Young has said she will seek to move a motion in the Senate to compel the government to produce documents surrounding any payments.

The auditor general has not yet responded to indicate whether he will investigate the use of funds. Any notice to produce documents in the Senate will likely immediately face a public interest immunity claim from the government which would allow them to refuse to provide the documents. Previous immunity claims have been made over other documents relating to asylum-seeker operations, which have sparked calls for a major overhaul of rules on the production of documents.

How has Indonesia responded?

Indonesia has reacted with concern to the allegations and said they will conduct an investigation into them. The country has raised repeated concerns about the policy of boat turnbacks to their shores. Relations with Indonesia soured again recently following the country’s execution of Australian drug smugglers Andrew Chan and Myuran Sukumaran.

Bishop has spoken out in unusually stern terms about Indonesia’s response. In an interview with the Australian newspaper, she made pointed comments about Indonesia enforcing its own borders if it wanted to “resolve any concerns it had” about the Australian government’s approach to asylum-seeker policy.