A boat carrying 153 Tamil asylum seekers including apparently sick children is likely to have run out of oil about 170 nautical miles off Christmas Island in high seas, refugee advocates say.

But Immigration Minister Scott Morrison is refusing to confirm the existence of a boat and says there are no significant incidents at sea to report.

Refugee activists said on Saturday the 21m boat which left from India on June 13 had sprung an oil leak and was expected to run out by lunch time on Saturday (AEST).

“We are experiencing huge waves and very bad conditions,” a man claiming to be aboard the boat told Fairfax Media via satellite phone on Saturday.

“We are very afraid and at threat. We have only three litres of water left. We can only manage for today, and tomorrow we will have nothing to drink.”

Two children on board – one aged three months, the other two years, were sick with vomiting, fever and headaches, he said.

“The wind is increasing. It is a very difficult situation.”

There are thought to be 32 women and 37 children on the vessel.

If it reaches Christmas Island it will be the first asylum-seeker boat to reach Australian shores in six months.

Opposition immigration spokesman Richard Marles said he had heard reports of a second boat from Java also nearing Australian waters.

Mr Morrison would not confirm if there was a boat, if it was in Australian waters or if the government was taking any action.

“No boat has arrived,” he told reporters in Melbourne.

The minister said the government’s border protection policies had not changed and that he would not comment on reports relating to Operation Sovereign Borders unless a significant event was involved.

“I am advised that I have no such report to provide to you today,” he said.

Mr Marles said Mr Morrison’s response was “a complete farce”.

“He’s very happy to beat his chest on the good days, but is silent on the bad,” he told reporters in Melbourne.

Mr Marles said he had no doubt Australian customs and the navy would do their job and provide assistance when it become necessary.

But Mr Morrison was reaching new lows by not commenting on what actions are being taken just because it was “inconvenient for his political scoreboard”.

Refugee Action Coalition spokesman Ian Rintoul said Mr Morrison’s attitude to the problem was “cavalier and dismissive”.

“We don’t want to see the government waiting until it’s too late,” he said.

Australian Greens senator Sarah Hanson-Young said turning the boat back to India was not an option.

“If the Prime Minister intends on creating a diplomatic row with India by attempting to turn the boat back, he needs to be up front about that,” Ms Hanson-Young said in a statement on Saturday.

“After nearly two weeks on board this boat these people will be extremely traumatised and in need of care.

“We should be offering this to them.”