The Boundary Commission for Scotland has launched an eight-week public consultation on the proposals, which would see the number of MPs returned to Westminster go from 59 in previous votes to 57.
Now MPs have urged the Commission to think again, warning it is an attack on both tradition and democracy.
Scottish Tory leader Douglas Ross faces seeing his seat scrapped in favour of three new ones called Highland East and Elgin, Banff and Buchan, and Gordon and Moray South.
Mr Ross, who has already ruled out standing again, has now hit out at the plans to “carve up” his constituency.
He said: “While I have already said that I will not be fighting the Moray seat at the next election, as the current MP I can’t support the proposals to carve-up the Moray constituency.
“It has been a huge honour to represent my home area as the local MP, but under these proposals, many historic local links would be lost and Moray’s identity diluted.
“The current seat works well as all the electors are within the Moray Council area and are represented by a single MP. Under these plans the same area would be represented by three MPs who would also be dealing with Highland or Aberdeenshire areas.
“The Boundary Commission need to go back to the drawing board and re-think these plans. I will be opposing them as I strongly believe the present Moray seat is best option for the area and local residents.
“I know the Boundary Commission have a difficult job, but I hope they will look again at their proposals and see that the correct decision is to maintain this long-standing seat.”
The proposals were also criticised by Jamie Stone, the MP for Caithness, Sutherland and Easter Ross, who faces his seat being abolished in favour of one called “Highland North”.
He said: “When these proposals were first mooted in 2018 I described the resulting constituency in the far north of Scotland as ‘stark raving bonkers.’ My position has not changed.
“It is clear that people living in the supersize constituency of Highland North would suffer a democratic deficit if these proposals were to succeed.
“Unamended, the new constituency would be 12,781 square kilometres in size, which would be the largest UK Parliament constituency by a country mile. To drive from one end of it to the other would take around three hours.
“In order to properly serve the electorate, MPs must be able to visit all parts of the area they represent and constituents must have the ability to access their MP. It is hard to see how that would be possible in a constituency like Highland North.
“Ultimately this proposal threatens democratic participation for people in the North of Scotland.”
SNP Westminster deputy leader Kirsten Oswald MP claimed the plans underlined the case for independence.
She said: “Tory plans to further reduce Scotland’s representation at Westminster, while increasing the number of MPs for England, underlines the need for Scotland to become an independent country – in full control of our own democratic decisions and with the full powers needed to build a stronger, fairer and greener future.
“The SNP will strongly oppose any attempt to weaken Scotland’s voice in the UK Parliament but the reality is Scotland will always be outvoted under the broken Westminster system – as we have seen with Tory austerity cuts, Brexit and power grabs imposed against Scotland’s will.”
Speaking at a press conference unveiling the plans, the deputy chair of the Boundary Commission for Scotland, Lord Matthews, had insisted the consultation is a “promising start”.
He said: “Thursday is the beginning of a process and we now want to hear the views of the public.
“We will reflect on responses to the consultation and make changes where appropriate and where the legislation allows us to do so.
“We strongly encourage voters to make their views heard.”