Key differences have emerged among the partners in the cross-party movement, which includes the Greens and Scottish Socialist Party (SSP). The SSP insist an independent Scotland should be a republic, rather than have an "un-elected, unaccountable hereditary monarch".
Led by former MSP Colin Fox, the Socialists also say any second ballot question should be about a republic rather than more powers for Holyrood. The SSP's position threatens to put the monarchy back at the centre of the independence debate, undoing Alex Salmond's painstaking efforts to neutralise the issue by promising an independent Scotland will keep the Queen as head of state unless voters decide otherwise in a second referendum.
However, in their submission to the Scottish Government's consultation on the 2014 referendum, the SSP make it clear they want the monarchy to end immediately after a Yes vote.
"We do not agree with the view.. [in the consultation] that 'Her Majesty The Queen would remain as Head of State' in an Independent Scotland. In our view the will of the people must be 'sovereign' both in the outcome of this referendum and in the Governance of our country.
"Scotland needs an elected Head of State not an un-elected, unaccountable hereditary monarch and we insist this profoundly important constitutional issue be resolved as part of the post referendum negotiations with the UK Government."
The Socialists' stance could embolden republicans inside the SNP, who until now have bitten their tongues for the sake of party unity.
Last week, SNP MSP Christine Grahame exposed the tensions in the party when she wrote a magazine article pouring scorn on the Royal family. She said: "After the Diana nonsense when complete strangers lemming-like threw themselves into publicity-driven grief, through Charles and Camilla's redemption, we are now spoon-fed the William & Kate Show, the latter ironically committed like her deceased predecessor to remaining stick thin for photogenic reasons".
SSP national spokesman Colin Fox admitted his party's position on the monarchy was "difficult to reconcile" with the SNP's.
He said: "The Yes campaign cannot be dominated by one party. There will absolutely have to be agreed positions within the Yes campaign on Nato [membership] and the monarchy. These issues need to be resolved within the Yes campaign."
A Labour spokesman said: "While the SNP desperately pretend little will change with their plans for separation, the SSP show just how different a separate Scotland would be."
Yes Scotland refused to comment.