The NAO conducted an informal review of the Teesworks project last year. It found no evidence of wrongdoing, though its remit only allowed officials to review whether central government grants were being used correctly.
The row follows a series of articles published by Private Eye that allege local property developers Chris Musgrave and Martin Corney have financially benefited from the site.
It was claimed Mr Houchen had allowed Mr Musgrave and Mr Corney to pay just £100 for land that was worth £100m. Questions have also been raised over how a large equity stake in the business has been transferred to the two men.
In a statement from Teesworks given to the BBC in April, Mr Musgrave and Mr Corney said they had “nothing to hide” and accused Middlesbrough MP and former Labour front bencher Andy McDonald of “an abuse of power”.
Mr McDonald has accused Mr Houchen of “industrial-scale corruption” using parliamentary privilege.
Mr Houchen responded by calling Mr McDonald a “coward” for not making his claims outside of parliament where he would not be protected from legal defamation claims.
The Metro mayor’s letter to Mr Gove continued: “While we continue to do everything that is appropriate and expected of a public body, in line with our reporting, scrutiny and transparency obligations, as we have since the start of this project, such grossly unfounded and inaccurate statements are now clearly impacting investor confidence at this site – and this is negatively affecting Teesside and UK plc.
“So we would also ask that such a review is done quickly so as to avoid investment and jobs being lost to the Teesside and the UK.”
The NAO said it was “likely to make further enquiries following our usual processes” as further government grants are expected to be made available to the Teesworks project.
It added: “This will involve liaising with relevant government departments and seeking to review relevant documents.”
