A council employee has been suspended amid an investigation that public buildings may have been sold for less than they were worth.

Audit Scotland and Aberdeen City Council are carrying out inquiries which centre on the sale of a building in the city's Carden Place.

The council decided that the building, Carden House, was surplus to its requirements and approved its sale together with adjacent land to a local medical practice at a price below its market value.

It is common for a public property to be sold below market value to another public body if taxpayers ultimately benefit. However, the property, for which it has been claimed a £1m offer was rejected, was sold to Medical Services Scotland for £590,000 in 2002.

It carried out a £2.75m refurbishment to the building and is now leasing it back to the Carden Medical Practice, which opened there last year, for a reported £500,000 a year.

A member of the public, understood to be a developer, has lodged a complaint with Audit Scotland which confirmed yesterday that it was investigating.

The complainant has said that he knows of a company which offered the council £1m for the property and land but the offer was turned down without any discussion.

Now the council is understood to be investigating up to 30 property sales to check for any irregularities. All relate to sales to NHS Grampian. It is also understood that David Beck, who works in the asset management department, has been suspended pending completion of the investigation.

An Aberdeen City Council spokesman said that as a matter of policy it did not comment on staffing matters but said: "A complaint was made by a member of the public to Audit Scotland over a property transaction involving a building which was owned by Aberdeen City Council. As part of our inquiries into that complaint on behalf of Audit Scotland, we are reviewing a number of property transactions over recent years to ensure that our investigations are thorough."

He said the police were not involved.

Audit Scotland confirmed that as part of its annual audit of Aberdeen City Council it was investigating the complaint about Carden House.

Because the property was sold at below market value the deal had to be approved by the Scottish Executive.

Councillor Neil Fletcher, who was convener of resources management at the time of the sale, confirmed that the property had been sold below market value.

"However, the councillors were under the impression that the building was being sold to NHS Grampian," he told The Herald. "In fact, it was being bought by a developer on behalf of the Carden Medical Practice. If we are given poor information there is little councillors can do about it."

No-one from Medical Services Scotland was prepared to comment.