Forest of Dean District Council announced that it was taking enforcement action against developer Crystalight Ltd because of unauthorised works it said had taken place at its site in the town of Newent.
The council said it launched an investigation after a complaint alleging that two dwellings had been built in addition to the nine that had been approved on appeal.
Other changes outlined in the planning officer’s report to last week’s planning committee meeting included changes to windows, alteration to the road layout and parking arrangements, and the reduction in one of the homes’ rear garden depth.
It was also found that the site had been "significantly enlarged, with a garage block located to the north of the site not constructed and instead additional dwellings being erected up to damp course level".
The report said: "It is clear that the development undertaken is fundamentally different when compared with the approved scheme. As a consequence, it is considered that all of the works undertaken on site are unauthorised."
The council’s enforcement notice ordered the developer to "demolish all of the building works and dig out all foundations, including any associated drainage".
It said the notice must be complied with within a deadline of nine months.
However, in a statement to Planning this morning, Hekmat Kaveh, chief executive of the Worcestershire-based firm, said: "We have lodged an appeal against the decision which was based on a large number of factual inaccuracies. We are positively confident that the appeal process will be successful."
The planning officer presenting the case at the committee said the developer had started demolishing the unauthorised works and claimed the site builder had started the works prematurely.
He added: "The developer is open to discussions seeking a way forward to avoid any costly appeals."