Former Liberal minister Stuart Robert has formally resigned from federal parliament.

Mr Robert, who announced earlier this month he planned to quit parliament, officially tendered his resignation in a letter to House of Representatives speaker Milton Dick on Thursday.

It came a day after Prime Minister Anthony Albanese described as “unacceptable” Mr Robert’s announcement that he planned to resign, but without setting an official date.

Mr Robert, the opposition’s assistant treasurer and spokesman for financial services, has also skipped trips to Canberra for parliamentary sittings, including for budget week. He continues to pocket his $200,000 taxpayer-funded salary.

Mr Albanese said voters in Mr Robert’s Queensland electorate of Fadden “deserved better”.

“He said that he’s resigning but he hasn’t resigned, so no date can be set for the by-election, but he’s not turning up to parliament. That is not business as usual,” he said.

Opposition Leader Peter Dutton publicly defended Mr Robert, saying it wasn’t “unusual at all” for a retiring parliamentarian to skip the long trip to Canberra.

Thursday’s resignation means a by-election date can be set for Fadden voters. A spokeswoman for Mr Dick said dates were being considered, with an announcement on timing to be made soon.

• Even after resigning, Robert is not far from controversy

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Mr Robert was first elected to the seat in 2007 and served in roles including employment minister, skills minister and NDIS minister during the previous Coalition government.

At the last election, Mr Robert suffered a 3.5 per cent swing against him.

The Coalition holds the safe seat by more than 10 per cent.

Two candidates have nominated for LNP preselection – Gold Coast Council planning chief Cameron Caldwell and former Queenslander of the Year Dr Dinesh Palipana.

Party nominations for the seat close on Friday.

On Wednesday, Prime Minister Anthony Albanese said Labor was yet to decide if it would contest Fadden, saying expectations about winning the very safe Liberal seat were “realistic”.

– with AAP