The UK government is being urged to scrap plans to reduce the number of MPs in Scotland.
Plans to cut the total number of MPs at Westminster from 650 to 600 would see the number of Scottish seats fall by six, from 59 at present to 53.
The Boundary Commission for Scotland has set out its latest set of proposals amid a series of public consultations.
But the SNP and Lib Dems have both now called on UK ministers to abandon the review of boundaries altogether.
There has been speculation that Prime Minister Theresa May plans to scrap the review due to pressure from her own back benches.
However, the UK government insists a review is necessary "to ensure fair and equal representation for the voting public".
Initial proposals for the new Scottish constituencies were published in October 2016.
An initial consultation drew 2,000 responses, and revised proposals have now been published and put out for further consideration.
Only three constituencies will be left untouched by the plans - Orkney and Shetland and Na h-Eileanan an Iar, which are protected under legislation, and East Lothian.
Some of the more notable changes would see Glasgow's representation cut from seven MPs to six, while seats in the Highlands and Islands would also grow in size but shrink in number.
The SNP said that "fiddling with the boundaries of MPs constituencies is the last thing the UK government should be wasting its time on".
MP Tommy Sheppard said ministers should "scrap their completely unacceptable plans to slash Scotland's representation at Westminster".
He added: "If the UK government is looking to reduce the cost of politics, the first priority must be abolishing the unelected, undemocratic House of Lords, which has zero accountability to voters despite having a ludicrously bloated chamber of over 800 taxpayer-funded peers.
"There is now no majority in the House of Commons for reducing the size of the chamber - for the Tory government to continue to task the commission to look at reducing seats is a waste of taxpayers' money."
'Bow to the inevitable'
The Scottish Liberal Democrats, meanwhile, claimed that the boundary review was "dead", saying that the DUP, which has supported Mrs May's Conservatives into government, would not back it.
Orkney and Shetland MP Alistair Carmichael said: "The DUP will not wear this review. Nor will many Tory backbenchers. The government should stop wasting public funds and bow to the inevitable.
"We will be making representations in the final eight-week consultation for retaining strong community ties, just as we have done at every stage of the review."
Scottish Labour also said they "oppose any proposals to cut the number of Scottish MPs", but added that they would engage with the process anyway.
Despite speculation that Mrs May is set to walk away from the proposals, which were included in the Conservative manifesto for June's snap election, the UK government has insisted that a review is necessary.
Constitution minister Chris Skidmore said: "A boundary review is needed to ensure fair and equal representation for the voting public across the United Kingdom by the next general election.
"Without any boundary reforms, constituencies would be based on data that is over 20 years old. This would disregard significant changes in demographics, house building and migration."
The latest Boundary Commission for Scotland proposals are now out for consultation until Monday, 11 December.
Lord Matthews, deputy chairman of the commission, said "careful consideration" had been given to comments submitted so far, adding that efforts had been made to implement suggested changes where possible.
He said: "This is the final opportunity we have to obtain views on our proposals so we can further improve them where the legislation allows us to do so. I hope people will take the opportunity to contribute, whether for or against what we have proposed."