Ministers now want to look at plans in more detail and have put an approval granted by Blaenau Gwent County Borough Council earlier this month on hold.

A government spokesman told ITV: “The holding direction provides the Welsh Ministers with more time within which to consider whether or not the application should be called in for their own determination.

“The Welsh Ministers have been asked to call-in the application and those requests are still under consideration.

“The holding direction provides the Welsh Ministers with more time within which to consider whether or not the application should be called in for their own determination.”

The holding direction prevents the council from granting planning permission but doesn’t stop the council from continuing to process the application.

Environmental campaigners have objected to the potential impact of the scheme.

Spanish giant FCC and local civil engineer Alun Griffiths (Contractors) have landed the construction contract from developer the Heads of the Valleys Development Company.

Work is due to start on the 830-acre development in late 2013 creating 3,000 new construction jobs.

Heads of the Valleys Development Company chief executive Michael Carrick said: “We are very confident in the outline planning application we have submitted and are delighted that we received the unanimous backing of Blaenau Gwent County Borough Council.

“The Welsh Government has asked for more time to look at the project and we’re happy to continue engaging with them and all stakeholders to ensure we address, as much as possible, the specific concerns they have.”