Liberal Party members from across the country are gathering in Canberra as the groping scandal surrounding expelled Victoria senator David Van continues to expand.

A third allegation against the senator was under investigation, opposition leader Peter Dutton confirmed while declining to provide further details other than that the accusation was being investigated.

Opposition Leader Peter Dutton and deputy leader Sussan Ley will address the annual federal council meeting on Saturday, which is being attended by state leaders, shadow ministers and senior office bearers.

Independent senator Lidia Thorpe and former Liberal senator Amanda Stoker both alleged Senator Van had touched them inappropriately in previous years.

Senator Van denied the allegations and said he would cooperate with any investigation process.

But Mr Dutton expelled the Victorian senator from the federal party room and later called for him to resign from parliament.

“The membership of the party is an issue for the party to resolve (but) I think it’s in everyone’s best interest that (Senator Van) resign from the parliament, and I hope he is able to do that sooner than later,” Mr Dutton told 2GB radio on Friday.

“I think that would be an appropriate next step.”

The Victorian division’s administrative committee will meet over the weekend to further consider the allegations.

The party has suspended all organisational resources and support from Senator Van.

Shadow treasurer Angus Taylor backed the opposition leader and “completely agreed” with his call for Senator Van to resign.

“When these allegations become clear, when people are prepared to make them they should be acted on and Peter has acted swiftly and that’s absolutely appropriate,” he said.

“These allegations are very serious from very credible people.”

Queensland opposition leader David Crisafulli and NT opposition leader Lia Finocchiaro will also address the council.

The two-day meeting provides an opportunity for council members to debate federal policies and discuss a range of issues.

Policy motions this year cover the issues of defence, child care, housing, cost of living and energy security.

The meeting is the first to be held since the fall of the coalition government last year.

The Liberals’ troubles worsened when they lost the blue-ribbon seat of Aston at a by-election in April.

Party officials are hopeful of retaining the Queensland seat of Fadden at the July 15 by-election.

— with AAP