Labour must put forward a confidence motion to attempt to topple the government, First Minister Nicola Sturgeon has said.
She repeated a warning that the SNP would act to table a no confidence motion in the government if Jeremy Corbyn’s party failed to do so.
A parliamentary confidence vote would trigger a 14-day countdown to a general election being called if it was supported by a majority of MPs.
Speaking on Sky News's Ridge On Sunday, Ms Sturgeon said a no confidence motion would "help clarify Labour's position" even if it failed to topple the Government.
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She said: "Labour's position right now is it won't back a second EU referendum until it has tried and failed to trigger a general election, but if it won't try to trigger a general election then we're in this catch-22 position.
"It seems to me right now that Labour is as much of a barrier to making progress on Brexit as the Tories are."
Labour have said a confidence motion will only be brought if it can be won. Other opposition parties can move a confidence motion, but are not guaranteed immediate parliamentary time to have it debated.
Ms Sturgeon added: “The SNP will keep all options open and if Labour won’t act, then we will act.”
Labour are understood to be wary of losing a confidence motion in case it boosts support for a second EU referendum as an alternative solution to the Brexit deadlock. Shadow Communities Secretary Andrew Gwynne told the BBC's Andrew Marr show that a confidence motion won't be brought until after the Commons get to vote on Theresa May's Brexit deal.
And asked about the prospects of a new Brexit referendum, Labour's shadow business secretary Rebecca Long-Bailey told Sky News: "I think we need to respect the referendum. I think there is a deal that can be struck within Parliament that brings everybody together."
She added: "In an extreme situation if that is not possible I share the position that our party has set out that we have to keep all options on the table.
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"And that we wouldn't rule out a people's vote at some point."
With several newspapers reporting that Downing Street and individual ministers were preparing for a second EU referendum, Education Secretary Damian Hinds denied it was an option.
Asked if Cabinet had talked about the issue, Mr Hinds told Sky News: "No. Government policy couldn't be clearer. We are here to act on the will of the British people clearly expressed in the referendum."