Mr Coe, 37, on Saturday revealed to The Canberra Times he would leave politics in March.

He led the Liberals to their sixth straight election loss at last year's October territory election, the party losing two seats in the process.

His former Liberal colleague James Milligan appears poised to replace him, with a countback in the Gungahlin-based seat of Yerrabi to decide who takes his spot in the Assembly.

Opposition Leader Elizabeth Lee said Mr Coe's forensic attention to detail was second to none.

Ms Lee, a moderate, took over the leadership from the conservative Mr Coe after the election loss. The party had faced criticism for failing to connect with the progressive Canberra electorate.

"He's been an outstanding local member. He held a very united team that took the party to the 2020 election," Ms Lee said.

"He's got a lot of experience in the Assembly, having been an MLA since 2008.

"He will be a great loss, not only as an MLA but of course as a friend. You do get to work closely with your fellow MLAs and you do develop friendships, and he will be a loss to the team."

She said he had been a steadfast advocate for vulnerable and poor Canberrans.

"Alistair has also been a great friend to our multicultural and faith communities, with a long history of outreach, advocacy and representation on their behalf," she said.

"I have no doubts that his contributions to Canberra and the Liberal Party will continue beyond his life in the Assembly."

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Chief Minister Andrew Barr said he wished Mr Coe well for the future.

"Politics is tough," he said. "Alistair was a formidable political opponent, a strong advocate for the conservative side of politics and, no doubt, his experience will be sorely missed by the Canberra Liberals in the years ahead."

Greens leader Shane Rattenbury said Mr Coe had shown a real dedication to his community and the issues he has championed since entering the Assembly.

"While we often disagreed heartily about issues, Alistair represented his beliefs and his constituency in a genuine and heartfelt manner," he said.

"Alistair also worked hard to engage the multicultural community in ACT politics - an important contribution to making Canberra a more inclusive city, and work that will strengthen our democracy.

"Having worked with Alistair on a number of committees and pieces of legislation over the years, I have always appreciated both his attention to detail and a willingness to find a way through contested discussions - something important in politics when you are trying to get the best outcomes for the community."

"On behalf of the ACT Greens, we wish Mr Coe and his family the best as he closes this chapter."