Australia's agriculture minister has been forced to resign after she was found to have steered public money to sports clubs in seats the conservative government was targeting ahead of an election.

Prime Minister Scott Morrison said Bridget McKenzie -- a former sports minister -- had resigned for failing to reveal she was a member of one of the shooting clubs that received taxpayer cash.

Morrison, who is already facing heavy criticism for his handling of Australia's months-long bushfire crisis, insisted he had dealt with the week-long grants scandal in a "stable, calm and careful" manner.

McKenzie had reportedly ignored recommendations from Sports Australia about who should get the money, instead funnelling it to areas that would help the ruling coalition.

The issue was politically fraught for Morrison, with McKenzie also acting as the deputy leader of his vital coalition partner, the Nationals.

Morrison claimed she "obviously did not stand to realise any pecuniary or any direct personal benefit".

Some of the projects included thousands of dollars to build female changing rooms at a rugby club that did not have any female players, in the marginal seat of Sturt.

A list of potential projects were reportedly colour coded according to which political party held the seat or whether it was a coalition target.

The opposition Labor party implicated Morrison in the scandal, alleging McKenzie was a "player sacked for following the coach's instructions".