Northland Regional Council member and Regional Transport Committee chairman John Bain said a new electronic swipe card system will replace the existing voucher system.
"This will be much easier for both users and drivers, more efficient to administer and enable better data collection," Mr Bain said.
Other changes include lifting Whangarei urban boundary restrictions.
Children 11 years and over who meet eligibility criteria will also be included, and a minimum $4 fare requirement scrapped.
Depending on demand, the yearly cost of the scheme could rise from up to $100,000 to $300,000.
"Even if the scheme costs do reach that new $300,000 maximum, those extra costs will be met solely by the NZTA, which will see its annual contribution increase from $80,000 to $180,000," Mr Bain said.
The district council's annual spend will remain capped at $120,000 while the regional council will pay the separate $20,000 annual administration costs.
The Total Mobility Scheme has more than 1200 registered users living in the Whangarei district.