The Morrison government is at risk of losing one of its safest seats, with former independent MP Rob Oakeshott launching a carefully plotted return to federal politics after six years on the sidelines.

Mr Oakeshott will contest the northern NSW seat of Cowper, which the Nationals hold on what should be an impenetrable margin of 12.6 per cent but could lose through a potent combination of the government's poll slump and the retirement of popular sitting member Luke Hartsuyker.

Rob Oakeshott left the Parliament in 2013 but is mounting a comeback. Credit:James Brickwood

Mr Oakeshott planned to announce his entry on Wednesday but brought it forward to Tuesday after The Sydney Morning Herald and The Age revealed his decision. The former MP will campaign on a platform of health, education and highways in the regional electorate, which stretches from Port Macquarie in the south to Coffs Harbour in the north.

The seat has been held by the Nationals since 1919 with the exception of just two years in the 1960s.