Liberal Democrat leader Vince Cable is to urge the SNP to back his campaign for a new referendum on Brexit.
The party wants the public to be given a vote on the final exit deal negotiated between the UK and the EU.
First Minister Nicola Sturgeon has previously said such a vote could become “very hard to resist”, but has stopped short of fully endorsing it.
Mr Cable will tell conference delegates in Aviemore that “time is running out” for the campaign to stop Brexit.
He will say that SNP votes could prove “crucial” to making a second referendum actually happen.
Scottish party leader Willie Rennie, who addressed the conference on Friday, has previously held talks with Holyrood Brexit minister Mike Russell in a bid to win the SNP over.
Ms Sturgeon has hinted she may back a second vote, calling Brexit process “a complete and utter car crash”.
She told the New Statesman magazine in October 2017: “The very fact that we have no idea what the final outcome might look like suggests there is a case for a second referendum that I think there wasn’t in 2014. It may become very hard to resist.”
‘Exit from Brexit’
Mr Cable is expected to tell Scottish Lib Dem members that the campaign for a “people’s vote” is “building in strength every day”.
He will say: “I am pleased to see people from across the political spectrum getting behind it. But a notable absence is the SNP. My party is working with the SNP to keep the UK in the single market. But it is not enough for the SNP to lament the consequences of Brexit, and of leaving the single market.
“In today’s political environment, Brexit is not – or doesn’t need to be – inevitable but time is running out for the SNP to play their part in stopping it.
“The only way to ‘exit from Brexit’ is through a people’s vote on the deal, with an option to stay in the European Union instead.
Mr Rennie used his speech to urge voters disillusions with other parties and Brexit to “try the Liberal Democrats”.
He said the party was the best “progressive alternative” for people who want to move on from the “division” of Brexit and independence.
Delegates have also been debating policy resolutions, with unanimous backing for an independent review of Scotland’s single police force and a halt to the merger of the British Transport Police into Police Scotland north of the border.
Party members also called for sweeping changes to abortion law, calling on the government to remove all existing criminal sanctions on having or providing a safe abortion.
The debate was led by 15-year-old activist Jessica Insall, who argued that abortion should be taken out of the justice system altogether and instead carefully regulated by the medical profession.
Although a handful of delegates spoke out against elements of the policy motion, which also includes a call for the government to fund free abortions for all service users regardless of their nationality or country of residency, it was overwhelmingly passed in the final votes.
Saturday’s conference session will include a call for the UK government to put pressure on Royal Bank of Scotland to halt branch closures and a resolution for changes to let people stand for election from the age of 16.