Australia's Immigration Minister Scott Morrison  arrived in Colombo this morning  as a group of Sri Lankan migrants controversially turned back by Canberra at sea said they were treated worse than dogs.

Minister Scott Morrison was to join President Mahinda Rajapaksa at the formal commissioning of two refurbished boats Australia gifted in November to tackle people smuggling, an official said.

"The President and the visiting minister will be at the commissioning of the two boats at the Colombo harbour," an official of the president's office said ahead of the ceremony.

It comes a day after a boatload of 41 Sri Lankans forced back by Canberra said they were abused, given little food and water and taunted with racial abuse.

The claims came as Australia faced growing pressure over its controversial immigration policies with High Court action under way in Sydney over the fate of 153 Sri Lankans being held in custody on the high seas.

They are currently detained on a Customs boat as lawyers argue that any transfer back to Colombo would be illegal, with concerns about the way they were screened.

Australia maintains that they screened the would-be asylum seekers at sea for possible refugee status before being handed over to the Sri Lankan navy earlier this week, but most of those returned told AFP that they were not given a proper hearing.

Many said they did not intend on making an asylum claim in Australia but instead were on their way to New Zealand in search of jobs when their fishing trawler ran out of diesel and water near Australian waters.

The boatpeople who were brought to Sri Lanka's southern port city of Galle on Monday and taken before a judge who released most of them on bail.

Out of the 41 boatpeople, the judge discharged nine children, including a two-month-old baby, and granted bail for another 27 while detaining five people on additional charges of organising the people smuggling boat ride, AFP reported.