Federal corruption watchdog needed: Milne

The Australian Greens have stepped up calls for a national corruption watchdog after Assistant Treasurer Arthur Sinodinos was enmeshed in a NSW Independent Commission Against Corruption inquiry.

The ICAC inquiry has heard Senator Sinodinos - who in 2008 was NSW Liberal Party treasurer and a member of the board of Australian Water Holdings - stood to gain tens of millions of dollars if the deal between the privately-held AWH and state-owned Sydney Water went through.

The Senate spent Wednesday morning debating whether he should explain inconsistencies between a statement he gave to parliament in 2013 and evidence heard at the corruption inquiry.

Australian Greens senator Christine Milne told reporters it was not a good use of the Senate's time for the government to be running a "protection racket" for the minister.

"He hasn't shown his face all day," she said.

Senator Milne said the revelations added weight to the Greens' push to set up a federal body.

"We wouldn't know about this if it wasn't for ICAC in NSW. We need to elevate this to the national level," she said.