Activist group GetUp! is readying itself for a costly legal battle to resist a new push to have it declared a "front" for Labor and the Greens.

The left-wing group says the latest attempt to have it officially linked under electoral laws to the political parties is "the greatest threat our independent grassroots movement has ever faced".

A GetUp supporter hands out how-to-vote in the ACT in 2013. Credit:Scott Hannaford

Coalition MPs led by hard-right Liberal senator Eric Abetz have long wanted the Australian Electoral Commission to label GetUp! a partisan "associated entity" - the name given to unions and fundraising vehicles such as Parakeelia and the Cormack Foundation, which have direct links to a political party. The AEC is now weighing the move.

If it happened GetUp! would lose its independent status and be forced to lodge financial disclosure returns to the AEC or face possible criminal sanctions.