Borkowski picked up the TGI Friday's account in 2007. It is understood to have brought in £3,250 per month for Borkowski.
However, Borkowski MD Larry Franks told PRWeek that the agency required fees to be 'healthier than that'.
He added: 'The decision was made after Borkowski won some new business. We decided to take stock of our accounts.'
Franks added that the decision to ditch the account because of low fees was not being applied to other accounts.
However, in a prepared statement, TGI Friday's commercial director Darrell Wade said the change in agencies was a result of the restaurant chain wishing to 'inject fresh thinking to help continue to drive TGI Friday's in the right direction'.
3 Monkeys won the brief after a competitive pitch.
The agency was recommended to pitch for the consumer account by Borkowski.
The brief is being led by 3 Monkeys associate director Anna Speight, who declined to comment on Borkowski's dropping of the account, other than to say the client was 'going through a big change'.
Speight was unable to provide more information about the work the agency would be doing for TGI Friday's or how much the brief was worth. She said: 'We're looking forward to working with them.'
At Borkowski, the three-strong team was led by account director Kathryn McAuley.
Last August, Borkowski plotted a PR drive to reinvigorate TGI Friday's, after the restaurant chain was fined £30,000 by Westminster Council for breaching six food hygiene laws.
Separately, Japanese restaurant group YO! Sushi has briefed 3 Monkeys Communications to generate publicity for its new restaurant launches this year.
The agency has been called in after a three-way pitch to handle the in-house press office as part of the three-month project.