Officers from the Stafford Borough Neighbourhood Policing Team (NPT) have moved to assure residents that they are safe after the discovery was made in Stone.
Police were called at 12.45pm on Tuesday to a premises on Swynnerton Road.
The rounds were discovered during excavation works at the building site.
Officers ordered that all works cease and set up a 50-metre cordon.
All workers were moved away from the site, which remained closed on Wednesday.
Staffordshire Police’s Explosive Ordnance Disposal Unit were currently working with the army to establish safe disposal of the items which was expected to be completed later on Wednesday.
Inspector Laura Morrey, of Stafford Borough NPT said: "I would like to reassure the community that we are doing all we can to protect them during the safe removal of the rounds.
"Although the rounds are wet and unlikely to detonate, we are taking all of the necessary steps to ensure they are disposed of as safely and effectively as possible.
"All work has stopped at the site and specialist disposal units are working at the scene today to ensure the items are disposed of appropriately.
"If you do come across any unexploded devices, please do not attempt to move or tamper with them under any circumstances, maintain a safe distance if possible, normally 100 metres, and alert others.
"Whenever possible, call 999."