The proposed National Housing Trust would rent out the properties to middle or low income families who don’t qualify for help from a conventional housing association and can’t afford to rent in the private sector.

A “cautious” estimate suggests the new landlord could buy 2,000 homes using almost £200million borrowed by local government.

The plans were discussed in private at a bumpy meeting of council leaders on Friday.

Some are concerned by a lack of detail about the plan and whether it is being driven by developers rather than genuine housing need.

Labour and the Tories last night called the scheme “half-baked” and urged ministers to reconsider.

Earlier this year, the SNP Government gave local housing associations £17m to buy unsold new housing to rent out at affordable rates.

The new plan is far more ambitious, effectively creating a state-run national landlord.

Communities Minister Alex Neil is understood to be the driving force behind the policy.

The proposal has been the subject of secret talks between government officials and the Convention of Scottish Local Authorities (Cosla) since June.

In August, the Government held a “snap consultation” with individual councils, with some authorities given just 72 hours to respond.

According to a paper before Cosla on Friday: “The National Housing Trust will be a vehicle for buying unsold homes from house builders and renting them out for ‘mid-market rent’... a form of affordable housing for low/moderate income households that are not eligible for mainstream social housing and that cannot afford rent levels in the private rented sector”.

Homes would be leased on Short Assured Tenancies then sold off after five to 10 years.

The money to buy them would be raised by local government using its limited borrowing powers, then repaid when the houses were sold.

There would be no direct government funding.

The SNP’s advisory body on investment, the Scottish Futures Trust (SFT), has been ordered to develop a detailed business plan.

According to the Cosla paper, the SFT has already received expressions of interest from 18 of Scotland’s 32 councils.

“SFT have also suggested that a cautious figure of 2,000 units could be provided if the proposals are implemented. SFT estimate that 1,000 homes would require around £91m borrowing from local government, with the private sector contributing an additional £49m.”

The proposal is for the National Housing Trust to be run by a “tripartite board” made up of central government, councils and banks.

This would oversee a string of “Special Purpose Vehicles” for each housing development site.

Councils would lend money to the Vehicle in their area, and have a say in which sites were used.

But Cosla remains concerned “on a number of fronts”, including the scant detail from ministers, lack of evidence about public demand for mid-market rent, and councils being able to borrow less money for other infrastructure works if they have to prop up the NHT.

“There are concerns that this is yet another quango,” the Cosla paper adds.

The NHT will be discussed by council leaders in greater detail in January.

Jim McCabe, Labour leader of North Lanarkshire Council, was dismissive of the plan.

“The National Housing Trust, to my mind, would be another expensive quango, duplicate work that’s being done by councils and social landlords, and dictate to us what we can and can’t borrow,” he said.

Tory housing spokesman Jamie McGrigor said: “The SNP must resist rushing through a secret deal to create another quango.

“They must look at all the options, especially the greater use of local housing associations close to the community. When it comes to housing, big is not usually beautiful.”

Labour spokeswoman Cathy Jamieson said: “This is another half-baked scheme from the SNP that is quite rightly being ripped to pieces.

“The most appropriate people to manage housing are housing associations and local authorities. Alex Neil has lost his grip if he thinks his latest idea will work.”

A Scottish Government spokeswoman said: “We are exploring new and innovative ways to provide the best value for money affordable housing possible. We have discussed a range of options with councils and no decisions have been taken.”

A Cosla spokesman said: “We do not comment on private meetings.”