The nation's highest court has rejected an application to hear an appeal from newly expelled Liberal member Matthew Camenzuli, who has been pushing to have the intervention ruled invalid.

Chief Justice of the High Court Susan Kiefel said there was "insufficient prospects of success" to warrant granting special leave to hear the appeal.

The High Court verdict, which comes after the NSW Court of Appeal tossed out Mr Camenzuli's case earlier this week, means a swag of candidates installed following the controversial power-grab are safe to contest the looming election.

Exactly when the election will be called remains up in the air with Mr Morrison refusing to reveal when he'll fire the starter's gun on the campaign.

Labor leader Anthony Albanese has accused Mr Morrison of drawing out the unofficial campaign to allow more time to use taxpayer funds to promote government policies and appoint Coalition allies to plum positions.

The High Court verdict draws a line under the messy preselection saga, which has exposed bitter divisions within the NSW Liberal ranks and provoked open hostility toward the Prime Minister.

The federal Liberal executive launched two temporary interventions into the NSW division after it failed to install candidates.

The first protected three sittings MPs from preselection challenges, with the second installing hand-picked candidates in a further nine seats - including Eden-Monaro.

Mr Morrison earlier this week said he intervened to protect "great women", including Environment Minister Sussan Ley, who was at risk of losing Liberal preselection in the seat of Farrer.

Immigration Minister Alex Hawke and North Sydney MP Trent Zimmerman were also saved in the intervention, which infuriated grassroots members who were denied a say over who would be their local candidate.

The NSW Court of Appeal tossed out Mr Camenzuli's case on the grounds it couldn't rule on an internal party dispute.

But Justice John Basten indicated that the intervention was valid given the broad powers under the federal executive's constitution.

The High Court verdict clears the path for Mr Morrison to call the election.

But there are no guarantees that will happen straight away.

The Prime Minister has until April 18 to call the election, with May 21 the latest date in which polling day can be held.

Mr Morrison signalled that he was prepared to run the full-term when peppered with questions about the election date on Friday morning.

"Well, electoral terms go for three years. The last election was on the 18th of May and the next election will be held at about the same time," Mr Morrison said.

More to come