The governor general, Sir Frank Kabui, announced the date yesterday and also informed MPs that nominations for the top job opened today and would close on Thursday.
Each prime ministerial candidate must be nominated by four MPs.
MPs cast secret ballots in the vote which will start at 9:30am at parliament.
In order to win, a candidate must secure an absolute majority of the 50 votes.
If there are several candidates and an absolute majority cannot be achieved voting will continue by rounds of elimination.