Mr Abrahams has said he never sought any favours from Labour

Communities Secretary Hazel Blears said she would liaise with other departments over the details of Mr Abrahams's plans for a business park in County Durham.

Her Tory shadow, Eric Pickles, said Mr Abrahams applied using the names of two employees and urged a review of rules.

An inquiry has begun into donations Mr Abrahams made to the Labour Party under the names of four associates.

Prime Minister has said the donations, which amount to more than �600,000 and were made over four years through four different people, were unlawful, "completely unacceptable" and would be repaid.

'True identity'

In the Commons, Mr Pickles said two of the people whose names were used for donations - Ray Ruddick and Janet Kidd - were also listed as directors of Durham Green Developments, which applied to build the 540-acre business park south of Durham City, near junction 61 of the A1.

He called for a review of planning rules to ensure an applicant's "true identity" was known.

What (was it) that first attracted the Labour government to the millionaire developer David Abrahams? Martin Horwood Lib Dems

And he added: "Can you explain why government objections to the building of a business park on the established green belt of County Durham were suddenly and unexpectedly withdrawn?"

"What steps were taken to ensure that the persons withdrawing the government objections knew the directors of the developers, Durham Green Developments, a Mr Ruddick and a Mrs Kidd, both employees of Mr Abrahams, made a substantial donation to the Labour Party?"

The development had been delayed by an order from the Highways Agency, over concerns it would increase congestion on the A1.

'Transparent' dealings

In response Ms Blears said the objection concerned the Highways Agency rather than ministers, but said it was "absolutely essential people had trust in the integrity and transparency of all of our systems in government".

She added: "You have raised some important questions and I will certainly undertake to liaise with my colleagues in other departments to ascertain exactly what has happened with regard to this issue."

She said the government would be "transparent in all of its dealings in this issue".

Liberal Democrat MP Martin Horwood asked her "what it was that first attracted the Labour government to the millionaire developer David Abrahams?" in a separate exchange.

Mr Abrahams has said he had never sought or expected any favours in return for his donations.