Abbott owes more detail on minister: Labor

Labor has questioned whether Prime Minister Tony Abbott has gone far enough in allowing a minister to stand aside rather than resign while anti-corruption hearings take their course.

Assistant Treasurer Arthur Sinodinos has stood aside from the ministry while the NSW Independent Commission Against Corruption (ICAC) probes the dealings of a company he formerly chaired, Australian Water Holdings (AWH).

Under questioning from Labor on Thursday, Mr Abbott said the minister had not resigned on Wednesday but had temporarily stood aside, accepting a backbencher's salary, not drawing on his ministerial expenses and having his staff redirected to the Finance Minister's office.

Opposition Leader Bill Shorten said this was not possible under laws governing ministerial pay and conditions.

"(The law) doesn't allow for this sort of half-pregnant proposition," Mr Shorten told parliament in moving to force the prime minister to make a 15-minute explanation.

Mr Abbott told parliament the senator had written letters setting out how he intended to spend his time while he standing aside.

In the letters - addressed to the Treasury secretary, Special Minister of State and Senate president - Senator Sinodinos wrote it was his intention to forego his ministerial entitlements.

"I ask that the ministerial component of my salary not be paid to me from today (March 19) until further notice," he wrote.

Mr Shorten said the prime minister owed the public an explanation about what had changed between his appointment of Senator Sinodinos as minister after the 2013 election and the events of this week.

"It is not appropriate (to say) ... it's a private conversation and that he doesn't need to explain his actions to anyone," the Labor leader said.

As the opposition grew frustrated in question time, Speaker Bronwyn Bishop warned: "Under the standing orders ministers are not obliged to answer questions ... merely because you don't get the answer you wish, does not make it outside the standing orders."

Earlier, Senator Sinodinos ducked journalists' questions, saying: "Let's talk to the commission."

ICAC has heard the former chief of staff to prime minister John Howard was paid $200,000 for 100 hours work with AWH in a bid to open communication channels with the NSW Liberal Party.

During his time on the board, AWH provided secret donations to the Liberal Party, which the party is paying back.

Senator Sinodinos denies any wrongdoing and will appear at ICAC as a witness.

No allegations have been levelled against him.

Mr Abbott told reporters the government was setting a new standard for ministerial ethics with the "brave" Senator Sinodinos doing the "right and honourable thing".

"If there are questions that need to be answered it's appropriate that people step aside until those matters have been resolved," Mr Abbott said.

Leader of the House Christopher Pyne told parliament Labor was showing "confected outrage".

"They are the party of sleaze and smear," he said, pointing to the scandals surrounding former MP Craig Thomson and NSW state Labor figures appearing before ICAC.

Shadow treasurer Chris Bowen said the assistant treasurer's sidelining would affect the government's planning for the May 13 federal budget.