There have been conflicting messages coming out of the party on how far the commission, due to report later this month, will go in areas such as income tax on welfare policy.
The intervention of the Shadow International Development with 200 days to go until the referendum is an indication of the recognition of the potential effect on the vote if the proposals are seen as half-hearted. He plans to say during a debate tomorrow at King's College, London that "further meaningful devolution to Scotland is compulsory".
He will add: "I know that most Scots are desperate to get rid of the Tories and many of us also want further powers devolved to Scotland from the House of Commons. Over the next year or so we can do both by voting to have more powers for Scotland and no Tories in Downing Street.
"In the last government I helped oversee the Calman Commission process which will see a big shift in tax powers in Scotland. I want the next Labour government to go further still on devolving power. It's for the Labour Party Devolution Commission to work through the detail but its crucial that we have an ambitious approach.
"Scotland has to hear from Labour loudly and clearly, that our future isn't a choice between this unacceptable Tory status quo versus independence."
While he refers to overseeing the Calman process as Scottish Secretary, he was seen then as a sceptic about giving too many powers to Holyrood. Mr Murphy has added his voice to that of Douglas Alexander, who made a similar speech last week.
The differences of opinion within Labour have been characterised as a Scottish Party with MSPs keen to push for more powers versus Westminster MPs resisting that trend.
The dangers of this approach will be highlighted today when Deputy First Minister Nicola Sturgeon makes a speech in Glasgow to the Scottish Convention for Development and Industry highlighting claimed reluctance and inadequacy of the plans coming from the Better Together parties.