He is after Liberal Senator Gary Humphries’ seat.

The high-profile grass roots lobbyist has the blessing of Greens leader Christine Milne, but he will have to wait at least a month to find out whether the ACT branch of the party accepts him.

Last night Senator Milne said: ‘‘I’m delighted that a young man of Simon’s integrity, passion and skills is seeking to join our strong parliamentary team.’’

‘‘The ACT Senate race could easily become crucial in stopping Tony Abbott from getting a majority in both houses and making Australia even less caring. Simon is very well placed to stand up to that threat.’’

Mr Sheikh is well-known in the ACT for the many Canberra-based campaigns he led as the face of GetUp!

He resigned from the lobby group earlier this year.

Last night Mr Sheikh said his passion for protecting Australia’s environment and strengthening its democracy was provable.

‘‘Canberra’s Senate seat sits on a knife’s edge,’’ he said.

‘‘If less than 1500 people who voted Liberal last election switch their vote to the Greens, we will change the course of the country by stopping Tony Abbott seizing one-party control of both houses of Parliament.’’

‘‘Last time this happened, the Liberals introduced Workchoices and wound back unfair dismissal laws.’’

Mr Sheikh said he would also campaign to protect public service jobs.

‘‘Canberrans deserve a Senator who’s empowered to really listen and represent them – not simply toe the line of the two old parties,’’ he said.