Mitch Roberts, town centre manager for the Berkshire town, told the Newbury Today website that the fundraisers, who were employed by agency Gift Fundraising for an unnamed charity, were behaving in an "extremely unprofessional" and "provocative" manner.
The agency denied the allegations. A spokeswoman said: "We have found no evidence to support the claims." She said the company, which recruits donors on behalf of many of Britain's largest charities, had received no official complaints.
Nik Earl, communications manager at the Public Fundraising Regulatory Association, said there had been tensions in Newbury for some time.
David Paull, a spokesman for Thames Valley Police, said: "We will be keeping an eye on things, especially in the build-up to Christmas."