Morrison: Robert has paid his penance

Prime Minister Scott Morrison has brushed off claims Stuart Robert shouldn't have been made assistant treasurer because of scandals earlier in his career.

Labor has attacked the appointment, with financial services spokeswoman Clare O'Neil saying Mr Robert is not fit to be in charge of Australia's superannuation savings.

Mr Robert was forced to resign from the front bench in 2016 for breaching ministerial standards after helping friend and Liberal donor Paul Marks sign a business deal in China while on personal leave.

"Those matters that were raised at the time have been fully addressed since," Mr Morrison told reporters in Sydney.

But that doesn't cut it with Ms O'Neil, who slammed Mr Robert's elevation to the ministry.

"Someone who was sacked for misconduct is going to be put in charge of fixing bank misconduct. It's a joke," Ms O'Neil told the ABC on Sunday.

"It shows that the government has never taken this royal commission seriously."

She said the role required a high level of ethics, but Mr Robert had shown he wasn't capable to be sitting on the front bench.

Last week Mr Robert said he had been cleared by federal police over the China incident, claiming to be one of the most scrutinised MPs in federal parliament.

Mr Robert also came under pressure last year after it was revealed he won his Queensland seat of Fadden in 2007 despite having direct links to a company awarded millions in government contracts.