The federal opposition says Prime Minister Malcolm Turnbull is protecting his "numbers man" by refusing to stand down embattled senior minister Arthur Sinodinos amid allegations of electoral law breaches.
Speaking on Saturday, deputy opposition leader Tanya Plibersek urged Turnbull to show leadership on the issue and stop pandering to the Liberal Party's right wing.
"The previous PM, Mr Abbott, was prepared to stand Senator Sinodinos aside while this matter or similar matters were investigated," Plibersek told reporters in Sydney.
"And you have to ask yourself why Mr Turnbull is less willing to act than Mr Abbott was. The only possible conclusion is that the PM, Mr Turnbull, needs to protect his numbers man in the face of a resurgent right wing of the Liberal Party."
The comments come after the New South Wales Electoral Commission alleged the NSW Liberal Party branch deliberately hid the identities of major donors to the 2011 state election campaign.
Labor has previously called on the PM to stand down Sinodinos because he was the NSW Liberals' finance director and treasurer at the time.
Turnbull has said that Sinodinos refutes the allegations.
Plibersek said there were many issues that Sinodinos needed to address about his time at the senior Liberal post.
"I think there's certainly questions around the individual role that Senator Sinodinos has played as the treasurer and finance director of the NSW branch of the Liberal Party while illegal donations were being channelled through the Free Enterprise Foundation," she said.
"There are questions around Senator Sinodinos' individual behaviour, there are certainly questions about the NSW branch of the Liberal Party."
Wow. Senator Arthur Sinodinos has released a seven page letter through his lawyers on Good Friday at 10pm... pic.twitter.com/f9aQYtmAYi— Mark Di Stefano (@MarkDiStef) March 25, 2016
NSW Premier Mike Baird admitted earlier this week that his party had not done the right thing and needed to "cop it on the chin".