Six Chinese men have successfully landed on Australian territory by boat, in an apparent blow to the Turnbull government's claims to have stopped the boats.

Fairfax Media can reveal that a boat carrying six Chinese nationals and an alleged Papua New Guinean people smuggler – all of whom were men – reached Saibai Island on August 20.

The boat that reached Saibai Island is understood to be much smaller than this asylum seeker boat from 2013. Supplied

Saibai Island is a low-lying island about four kilometres from Papua New Guinea and home to about 300 people. It is nearly 150 kilometres north of the Queensland mainland but is part of the state.

As recently as Monday, Immigration Minister Peter Dutton boasted that "we've not had a successful boat now in well over 1000 days".

One of the Chinese men and the Papua New Guinean man were arrested and charged with aggravated people smuggling, contrary to Section 233C.1 of the Migration Act.

The pair appeared in a Cairns court over the weekend and remain in custody. The other five Chinese men have been sent back to China. It is not clear what their motive was or whether they were asylum seekers.

A high-level source denied the arrival was a breach of Operation Sovereign Borders.

While the boat did manage to land on Australian territory, the government will likely argue that Saibai Island is much closer to Papua New Guina than it is to the Australian mainland and that it rapidly intercepted the unlawful arrival by the seven men.

The use of a small boat may also signal a shift in the methods used by people smugglers to circumvent Operation Sovereign Borders in their attempts to bring people to Australia.

Under Sovereign Borders, put in place by Tony Abbott and Scott Morrison in 2013, Australia has turned back asylum seeker boats at sea that have attempted to reach the Australian mainland.

Prime Minister Malcolm Turnbull has embraced the controversial policy, which has drawn heavy criticism from human rights and asylum seeker advocates, the Greens and sections of the Labor Party.

But it is regarded within the Coalition as one of the government's signature policy achievements and Labor, under Bill Shorten, has promised that it too would turn back asylum seeker boats headed for Australia if it wins government.

Last month, the government hailed the three-year anniversary of stopping asylum seeker boats reaching Australia.

At the time, Mr Dutton said that "since Operation Sovereign Borders commenced we have turned back or dealt with 31 boats and had those 31 boats got through, hundreds and hundreds of boats would have followed. So this problem has not gone away."

News of the arrival comes as the government has been under fire for plans to end income support for up to 100 Australian-based asylum seekers and give them just three weeks to find a home.

Bill Shorten has attacked the decision as the Prime Minister's "weakest move yet" and a "new low" but Mr Dutton has defended it, arguing the asylum seekers will have work rights, access to Medicare and that children will be able to go to school until they are sent back to Manus Island or Nauru.

A spokeswoman for the Immigration Minister declined to comment.