Sixteen Gypsy families have been told they must stop building on a camp in a Somerset village which they moved on to a week ago.
The families, who own a five-acre field at North Curry, installed septic tanks and started bringing in stone to build makeshift roads.
The group does not have planning permission for the new developments.
Taunton Deane Borough Council issued the stop notice which means they must stop building or face fines.
If they do not comply they could be fined up to £20,000.
Because the development breaches planning applications the council says it is also going to apply for an injunction to remove the gypsies from the land.