Constitutional Relations Secretary Mike Russell has written to the UK Government to raise concerns after ministers in Edinburgh were asked to participate in the sharing of data who used Government websites to seek information about Bexit.
It emerged today that the UK Government wrote, via the Government Digital Service on 2 September to ask the Scottish Government to participate in the process.
But Mr Russell has written to the UK's top civil servant, cabinet secretary Sir Mark Sedwill, ruling this out.
"I am not prepared to support the proposal in its current form," Mr Russell states.
"No such proposal could be considered until I have been provided with meaningful and demonstrable assurance that the data sharing complies with data protection laws, that the required safeguards are in place, and on the uses to which the data will be put."
Mr Russell adds: "I do not believe that a citizen using a website such as gov.uk or mygov.scot will be aware or expect that their personal data is being linked in this manner.
"Inevitably, this will raise concerns in the minds of people using our sites, as it does in mine, about the potential future consequences of information sharing of this nature.
"In particular, I believe that scope and nature of the linking of personal data is not proportionate to the avowed purpose, and the combination of Brexit data with other government service data raises questions about the use in future for campaigning purposes."