Mr Turnbull says his two-term reign representing the blue-ribbon eastern Sydney electorate will come to an end at the federal poll later this year.
Despite being a Liberal seat for more than 50 years, Wentworth is no longer a certainty at election time: It is held with only a 3.9 per cent margin.
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The Liberals will begin pre-selection for the seat on Friday, and competition is said to be fierce.
Turnbull planning return to business
Potential candidates for the party include Peter Doyle, from the Sydney seafood family, former Young Liberals' national president Jason Falinski, and Arthur Sinodinos, the onetime chief advisor to ex-PM John Howard.
For Labor, Graham Wedderburn, former chief of staff to ex-NSW Premier Nathan Rees, has reportedly been approached to challenge Mr Turnbull's replacement.
Mr Turnbull is contemplating a return to his business interests, although there hasalso been an invitation from the NSW opposition to join the state political ranks.
Mr Abbott said Mr Turnbull still had a lot to offer, whatever he chose to do next
"He has a big contribution to make to our country in the future," he told ABC Television. "Whether it's to business, whether it's to some form of public life, that's got to be Malcolm's decision."
