Norwich & Peterborough Building Society will restrict access to its mini-cash Isas from May 22.
The restrictions mean Isa accounts must be opened in person at one of the society's regional branch network in East Anglia.
The constraints are imposed to prevent speculative activities from carpetbaggers.
The move does not effect existing N&P customers.
The society is the latest building society to attempt to head off the carpetbaggers by restricting the opening of accounts. Its announcement follows recent moves by the Skipton, Chelsea and West Bromwich building societies.