The Greens want a former federal government minister to donate to charity the $75,000 he was pocketing from a business lobby group while he was an MP.
Bruce Billson has written to the Clerk of the House of Representatives apologising for not disclosing he started receiving a $75,000 salary from the Franchise Council of Australia before he retired in mid-2016.
When initially asked whether he should have made the disclosure on the parliamentary register of interests Mr Billson told ABC-TV's 7.30: "No, because I think it's nonsense and utter crap. But if it's something you want me to check out, I'm happy to do that."
He later responded by email: "(It) was a discourtesy to the House of Representatives and an administrative failing of my behalf not to lodge a timely formal disclosure statement before the Parliament was prorogued."
Greens senator Lee Rhiannon says the apology is not good enough and the money should be donated to charity.
"The former small business minister should be required by the prime minister and the Liberal Party to donate to charity the salary he received while breaking parliamentary rules," she said in a statement on Wednesday.
"What is the point of having rules for MPs and ministers if they can be breached with no consequences."
The clerk's office declined to comment on individual cases or correspondence when contacted by AAP.
According to parliamentary rules failure to declare income sources could be contempt of parliament.