Joanna Cherry made it clear she would not wish to "replicate the violence" that preceded the creation of the Irish Republic just over a century ago.
But the Edinburgh South West MP says in a article for The National newspaper on Friday the republic was established after a majority of pro-Nationalist MPs were returned in the Irish election of 1918 and suggested this could be the template of a “Plan B” for Scottish independence – if demands for a referendum continue to be rejected.
Her suggestion comes ahead of a major SNP assembly later this month to discuss the tactics for achieving independence.
Although the party's justice spokeswoman at Westminster says a legally binding referendum would be the favoured way to achieve independence, Prime Minister Boris Johnson has so far ruled this out.
"It is foolish and dangerous to rail against having a plan to do things differently should it be required," Ms Cherry says in an article for The National.
The MP says it is "patently not true" that a referendum is the only way to bring about independence.
"One hundred years ago, Irish independence came about not as a result of a referendum, but as a result of a treaty negotiated between Irish parliamentarians and the British Government after nationalist MPs had won the majority of seats in the 1918 general election and withdrawn to form a provisional government in Dublin,” she adds.
"While no-one wants to replicate the violence that preceded those negotiations, the Treaty is in legal and constitutional terms a clear precedent, which shows that a constituent part of the UK can leave and become independent by a process of negotiation after a majority of pro-independence MPs win an election in that constituent part."
Polls show the SNP is on course for a landslide victory in May's Holyrood election, which could even see the party return a majority of MSPs, similar to the outcome of the 2011 Scottish election that prompted the UK Government to agree to a referendum on independence in 2014 through a section 30 order.
But the constitution in the UK is reserved to Westminster and Mr Johnson has ruled out a repeat of the 2014 vote.
An SNP virtual assembly is to take place on January 24, which will discuss the "tactics and strategy on the route from here to Independence day".
The Scottish Government has been demanding the right to hold another referendum on independence in the aftermath of Brexit vote in 2016, which saw two-thirds of Scots opt to remain in the EU, but the weight of votes south of the Border swung the outcome in favour of Leave.
But a Uk Government spokesperson added: “All our focus should be on dealing with the pandemic. The last thing people in Scotland want or need is another divisive referendum.”
Ms Cherry’s comments were branded “irresponsible” by Pamela Nash, chief executive of Scotland in Union.“The comparison with what happened in Ireland over 100 years ago is insulting,” Ms Nash added.“Ignoring the views of the people of Scotland and leaving the UK by the back door would be a democratic outrage.