Former planning Minister Matthew Guy is Victoria's new opposition leader, having defeated Michael O'Brien for the top job.

Mr Guy emerged from a drawn-out party-room meeting to declare he was "absolutely humbled and overwhelmed".

Victorian opposition leader Matthew Guy. Credit:Enrique Ascui

"I am deeply appreciative of the trust the parliamentary Liberal Party has given me today," Mr Guy said.

Mr Guy moved down from the lower house to contest the seat of Bulleen at last week's election. He is regarded as one of the Liberal Party's stronger performers.

Former ports minister David Hodgett was elected deputy in the lower house, with former community services minister Mary Wooldridge elected Liberal leader in the upper house. Gordon Rich Phillips will be deputy leader in the upper house.

Former premier Denis Napthine said he believed Mr Guy would be an outstanding leader of the Liberal Party.

"He is young, dynamic, he really knows how to relate to people. We are very fortunate in the Liberal Party that we have an enormous depth of talent," Dr Napthine said.