Work taking place on the Church Street site.
There had been no activity on the former Minster School site on Church Street since a planning application for 29 homes was rejected.
But concerns were raised when heavy machinery, including JCBs, were spotted carrying out work.
The site is believed to contain the remains of a Roman villa and archaeologists hope it could provide the link between the Roman occupation of Southwell and the building of the minster.
Town councillor Mrs Sue Rodgers, a former member of Nottinghamshire County Council’s archaeology team, said the county council’s archaeologist Ursilla Spence was aware of the investigations taking place.
Mrs Rodgers said: “There are no worries about the archaeology on site. The work is further archaeological work being carried out, not building work.”
Mrs Rodgers said she had been liaising with the landowner, Caunton Properties Limited, and heritage groups to try to reach a compromise over the future of the site.
She said: “No one has come forward to say they are interested in a compromise so for the time being it is all on hold.”
Mr Peter Kent, a member of the Roman Heritage Park campaign group, which wants to see the site turned into a heritage park, said the group had concerns about the work taking place.
He said: “I have been approached by several people enquiring about what is happening.
“Ursilla Spence has assured me that it is all under control and the work is being carried out by Preconstruct Archaeology, which is a reputable firm.
“There have been a lot of rumours going around about the site.”
Mr Kent, also a member of Southwell Archaeology, said the group would like there to be more information available about work taking place.
He said: “Some of the treatment looks pretty brutal but it looks as if it is quite an extensive archaeological investigation.
“There is so much speculation there and that would be much better if the groups were involved.”