Wallaby great and environmental activist David Pocock was poised to win a seat in the Australian Senate Sunday and become the first independent to hold the role for the national capital Canberra.

The former flanker, who earned 78 caps for Australia before retiring in 2019, is on the verge of unseating Liberal senator Zed Seselja, state broadcaster ABC reported, although votes continued to be counted.

The 34-year-old ran as an independent in the Australian Capital Territory (ACT), which includes Canberra, where he played for seven years with the Brumbies Super Rugby team.

"We've clearly shaken up politics in the ACT," he said in thanking his supporters.

The Zimbabwe-born Pocock stood on a campaign of more action on climate change, improving integrity of the political class, helping poorer Canberrans and standing up for women's rights.

Outspoken during his playing career on issues such as LGBTQ rights and climate change, he always rejected barbs from critics that athletes should stick to sports.

Rugby great David Pocock is poised to become an Australian senator Rugby great David Pocock is poised to become an Australian senator Photo: AFP / William WEST

He was arrested in 2014 for chaining himself to a digger in a protest against a coal mine being opened in a forest in New South Wales.

Pocock announced his move into politics last December, saying he wanted to use his platform for positive change.

"Now, more than ever, we need political courage," he said then.

The Senate, parliament's upper house which reviews legislation put forward by lawmakers in the lower house, has 76 representatives, 12 from each of the country's six states and two from the its two territories.

Both ACT senators have always come from the ranks of the two major parties -- centre-left Labor and the conservative Liberals -- making Pocock's impact all the more impressive.

ABC said Labor's Katy Gallagher was set to retain the other seat in the ACT.