ACT Electoral Commissioner Damian Cantwell declared the former public servant the winner of a countback of 2016 ACT election preferences in the seat of Kurrajong on Wednesday.

Ms Burch is expected to formally take up in the Assembly chamber in second week of February after ACT politicians return from the summer recess, replacing Steve Doszpot who died last month.

An economist and former assistant director in the Department of Finance, Ms Burch was declared the winner of the countback on Monday but was not confirmed until the official announcement, as Elections ACT allows time for successful casual vacancy candidates to resign from any relevant public office if required.

Born in South Africa, she is a former staffer for Liberal Opposition Leader Alistair Coe and returned home from a working holiday in the United States and Canada to take up the vacancy.

Mr Burch has nominated housing affordability for young Canberrans as a key issue in the Assembly and described representing Kurrajong as an honour and a privilege.

She said this week her experience at Finance meant she would bring a good understanding of how government worked and the "unintended consequences of government decisions".

Mr Coe and deputy Nicole Lawder welcomed Ms Burch, calling her an active member of the community with a strong academic and professional background.

According to the 2016 election results, Ms Burch was the front-runner of all unelected Kurrajong candidates, having received 2859 votes or 5.9 per cent of the electorate's votes.

Her appointment makes the Canberra Liberals' partyroom majority women, coming a year after the ACT became the first Australian jurisdiction with a majority female parliament.

Women will make up 14 out of the 25 members of the parliament from 2018.

Mr Doszpot died after a nine-year career in the Legislative Assembly and a month after announcing he had terminal liver cancer.