The federal Liberal party has elected its first female leader, with Sussan Ley narrowly defeating Angus Taylor, 29-25.

Ley, 63, who was deputy leader to Peter Dutton during the last term, had the support of the moderates in the party.

Jacinta Nampijinpa Price, who defected last week from the Nationals to join a ticket with Taylor, pulled out of the deputy race after Taylor’s defeat. Taylor was supported by the conservatives in the party.

While Price has strong appeal in Liberal branches, the bold move backfired.

The new deputy is Queenslander Ted O'Brien, 51, key architect of the opposition’s controversial nuclear policy, which many considered a serious drag on the Coalition’s election vote. O'Brien defeated Phil Thompson, a fellow Queenslander, 38-16.

The closeness of the leadership vote is a recipe for instability dogging Ley’s leadership. Two of her supporters, Linda Reynolds and Hollie Hughes, are leaving the Senate on June 30.

In the Coalition government, Ley variously held the portfolios of health, sport, aged care and environment.

An immediate challenge for Ley will be reshuffling the frontbench, especially what roles Taylor and Price will have.

Ley has held the southern NSW regional seat of Farrer since 2001.