The Sri Lankan military says it has not intercepted a boatload of Tamil asylum seekers bound for Australia and it has no plans to do so.
The boat, believed to be carrying 150 asylum seekers including 37 children, has not been contactable since the weekend, indicating it may have been intercepted by the Australian Navy or Customs.
Those on board claim they are Sri Lankan, but began their voyage in India which is home to many Tamil refugee camps.
Refugee groups are concerned Australia handed the group over to the Sri Lankan Navy.
But a spokesman for the Sri Lankan military told the ABC that has not happened.
"There is no plan for the Sri Lankan Navy to take over asylum seekers bound for Australia from [the] Australian Navy," he said.
The spokesman says he believes Australia is taking them to Christmas Island.
The Australian Government is refusing to confirm or deny the boat's existence or its possible whereabouts.
A Sri Lankan Navy spokesman has denied having any official information about a boat transfer of asylum seekers at sea.
Media reports have quoted Commodore Kosala Warnakulasuriya saying a boat transfer is going ahead, but says that is not the case.
Commodore Kosala says he has no information about a plans for his Navy to receive passengers from either boat.
"No, no, no. I have not told anything like that," he said.
"Even in the morning I got the information that someone has quoted me about some Sri Lankan Navy boat movement but I have not made that sort of a comment."
Immigration Minister Scott Morrison has declined to comment on reports the boat had been intercepted, saying that starving people smugglers of information about their boats had successfully stopped them.
"In accordance with the policy established by the Operation Sovereign Borders Joint Agency Task Force commander, the Government does not comment on speculation or reporting regarding on-water operations," a spokesman for Mr Morrison said.
"The Government will continue to act in accordance with our international obligations, including applicable international conventions and to protect the safety of life at sea."
Mr Morrison accused Labor and the Greens of "doing the bidding of smugglers" by asking about the fate of the boats.
Greens condemn 'shocking and cruel' treatment of asylum seekers
Greens leader Christine Milne says sending asylum seekers back to Sri Lanka is the equivalent of sending the persecuted back to the persecutors.
"They have a shocking reputation for human rights," she told a press conference this morning.
"It is now up to Prime Minister Abbott. Prime Minister tell Australians - are you going to send 153 people back to the people who have persecuted them?
"Is that what this nation has become under your leadership? Because I think the overwhelming majority of Australians will be horrified by this.
"Not only is it shocking and cruel for the people who have been persecuted and are being treated like this, but it is absolutely in breach of our obligations under the refugee convention."
The director of the Human Rights Legal Centre, Daniel Webb, says he would be "surprised and disappointed" if the Government had returned the asylum seekers to Sri Lanka.
"There's lots of aspects of our policies that currently breach international law," he told The World Today.
"We detain people arbitrarily in inhumane conditions on remote islands, we remove their access to lawyers when they're undergoing that refugee assessment process in Australia.
"So there's lots of issues but just intercepting them and sending them straight back into the hands of the very people they fled is the clearest violation of international law imaginable."
Local authorities in India say they are not aware of any asylum seeker boat leaving the country's shores.