The SNP has called on Scottish Labour leader Kezia Dugdale to clarify her position on the renewal of Trident.
Bill Kidd MSP has written to Ms Dugdale asking her for clarification following a week of "absolute chaos" for the Labour party on the issue.
Labour MSPs Neil Findlay, Malcolm Chisholm and Elaine Smith have signed an SNP motion opposing the renewal of Trident - in a foretaste of the wider debate expected at the Scottish Labour Party conference later this month.
Meanwhile Labour leader Jeremy Corbyn and shadow Scottish secretary Ian Murray favour unilateral UK disarmament in the hope it will convince other countries to follow suit, but they are at odds with Labour's multilateralist support for Trident renewal.
UK Labour reaffirmed its support for Trident at its conference last month but Mr Corbyn caused confusion by admitting he would never launch a nuclear attack.
Mr Kidd said: "This has been another week of absolute chaos for the Labour party on the issue of Trident.
"The situation we are now in is one where the UK Labour leader, their deputy leader in Scotland, their only Scottish MP and two senior MSPs are all openly backing the SNP position on Trident, yet their UK conference just rubber stamped a renewal of these immoral weapons, while Kezia Dugdale does everything she can to continue ducking the debate."
He added: "It's time for Kezia Dugdale and Labour to stop misleading the people of Scotland on the issue. They have to be straight on Trident - will they back the SNP in getting rid of Trident or will they back the Tories in spending £100bn on weapons of mass destruction?
"In contrast the SNP's position is clear; the money should be spent on public services and supporting our young people, rather than on outdated, immoral weapons which are relics of the Cold War.
"Kezia Dugdale would be well advised to take heed and join with the SNP, the vast majority of Scots and the sensible voices inside her own party by opposing these abhorrent weapons."
A Scottish Labour spokesman said: "Under Kezia's leadership Scottish Labour is redemocratising the party conference and giving over Sunday as members day.
"If members choose to debate Trident that is what we will do. Whilst the SNP conference will show as much free will as the extras in the Walking Dead we actually have democratic debate in the Scottish Labour Party."