The report which recommends the public consultation, external said keeping the monthly fee at 80p would cost Tamar Bridge and Torpoint Ferries (TBTF) about £690,000 a year.
The reduced income would mean TBTF could face a deficit of nearly £1m by 2029/30.
The bridge and ferries are operated and maintained jointly by Plymouth City Council and Cornwall Council.
The report said if the monthly fee was not increased “further significant action will be required to increase income and/or reduce expenditure to avoid the reserve going into deficit”, with Plymouth City Council and Cornwall “required to provide revenue funding”.
The proposed increase has been opposed by Labour MPs and Luke Pollard, MP for Sutton and Devonport, said: “I hope that the committee abandons their new Tamar Tag charges and fully adopts cheaper tolls for local people.”
The monthly fee has been 80p since 2014 and there are currently about 56,000 Tamar Tag users.
Price increases for all tolls were approved in March 2025, with fares for cars and vans going up from £2.60 to £3.00, and fares for Tamar Tag holders increasing from £1.30 to £1.50.