A wall has collapsed at the Locks Hill development at Kingsbridge.
The retaining wall with an estimated 18 precast interlocking concrete blocks weighing more than two tons each collapsed this morning reportedly as it was being back-filled with soil.
The workers have been trying to make it safe.
District Councillor Julian Brazil said: "My first concern is the health and safety aspect. It's very worrying. Also of concern is the road to the rugby club. There was a footpath blocked but we have been told it is now clear."
Blakesley Estates are constructing 32 houses at the site.