Papua New Guinea's Treasurer, Bart Philemon, says he will challenge the prime minister, Sir Michael Somare, for the National Alliance leadership at the party's two-day convention beginning on Thursday.
Mr Philemon was stripped of the finance portfolio in a cabinet reshuffle recently, and the position was given to Patrick Pruaitch, who is also forest minister, and the acting National Planning and Monitoring minister.
The newspaper, The National, reports that the Lands and Physical Planning minister, Dr Puka Temu, nominated Mr Philemon and that Mr Philemon informed his party last week that he was accepting the nomination.
An official says Mr Philemon is disappointed that the Prime Minister took the finance portfolio away from him.
Party insiders have told the newspaper that if Mr Philemon fails to get elected, he will resign.