Peter Costello ended his 19-year political career with a letter to the House of Representatives Speaker and a 20-minute press conference, rather than a final flourish in the parliamentary chamber.

Mr Costello's responses were also economical when asked about his plans for the future, saying he would take up a role in the ''private sector''.

He was more lavish on other fronts. ''I've had a great career in public life,'' he said. ''I leave with the feeling that I made our country a better place.''

Mr Costello was equally extravagant in his critique of the Rudd Government's ''low-quality spend'' to stimulate economic activity amid the global financial crisis.

''A government is much better if it lives within its means,'' he said.

''A spendophile is a much easier condition to get to than a debtophobe ... spending is the easiest condition in the world. The hard thing is to balance a budget.''

Mr Costello believed the Liberal Party would go through a rebuilding process in Opposition, which was a great time for young people.

And there was ''every opportunity'' for Opposition Leader Malcolm Turnbull to win the next federal election in a ''two-horse race''.

Mr Costello remarked he had had a ''wonderful ride''.

''My friends in the press gallery, I will miss you all, more than you can believe,'' he said.

''I thank you for keeping me honest for all of those years.''

Former Opposition leader Brendan Nelson also handed in his resignation letter yesterday and is bound for Europe to take up a diplomatic post.

The resignations trigger by-elections in Bradfield and Higgins, but House of Representatives Speaker Harry Jenkins is still considering dates.

''I am consulting with party leaders and independent members on this matter. I will inform the House in due course of the dates which I have fixed for the by elections,'' Mr Jenkins said.