Prime Minister Tony Abbott has continued to insist the royal commission into trade unions will go on, regardless of whether commissioner Dyson Heydon disqualifies himself tomorrow.

The Australian Council of Trade Unions has applied to disqualify Mr Heydon over his acceptance of an invitation to speak at a Liberal Party function.

The commissioner conceded he “overlooked” the connection between the Liberal Party and the Sir Garfield Barwick oration and later withdrew from speaking at the function.

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He will hand down his ruling on Friday morning.

“The importance thing is that the Royal Commission will continue,” Mr Abbott said.

“We have seen an abundance of evidence of rorts, rackets and rip-offs inside the union movement.

“We have seen an abundance of evidence of union officials ripping off workers to help themselves, ripping off workers to push their own personal barrows inside the Labor Party.

“It must and will go on, regardless of any decision.”