The independent MP who propped up the Gillard government will make a fresh bid to return to Parliament, setting up a three-cornered contest in a key NSW seat at next year's federal election.

Rob Oakeshott is expected to announce his decision to re-enter federal politics shortly, and will face a fiery attack from Labor and the Coalition who are both preparing to campaign against the 49-year-old former MP.

Cowper, which the Nationals hold on a very healthy margin of 12.6 per cent, should be considered a safe seat but the impending retirement of Luke Hartsuyker as the local member for 17 years throws the contest wide open.

Former independent MP Rob Oakeshott is expected to mount a comeback. Credit:Andrew Meares

Mr Oakeshott, along with the Greens and independents Tony Windsor and Andrew Wilkie, entered into a supply and confidence agreement with Ms Gillard after the 2010 election. He made headlines for delivering a 17-minute speech announcing he would back Ms Gillard over the then opposition leader Tony Abbott.