Barr becomes ACT's new chief minister

Andrew Barr and Simon Corbell faced no opposition in the ACT Labor caucus to become the party's new leaders.

Andrew Barr has been elected unopposed as parliamentary leader of the ACT Labor Party. (AAP)

Andrew Barr will be the ACT's next chief minister.

Mr Barr was unopposed in his bid to become parliamentary leader of the ACT Labor Party at its special caucus meeting on Wednesday.

His deputy will be long-serving MLA Simon Corbell, who was also elected unopposed.

The leadership changes were necessary after Katy Gallagher resigned as chief minister to contest Labor preselection for a soon-to-be-vacated Senate seat.

The ACT Legislative Assembly will hold a special sitting on Thursday to formally elect Mr Barr as chief minister.