More than 50 older drivers in the Western Bay have been referred by their doctors to sit on-road safety tests this year - with half failing.
Figures released under the Official Information Act show 52 on-road safety tests were carried out this year for drivers aged 74 or older in Tauranga City and two in the Western Bay of Plenty district - with 48 per cent and 50 per cent respective pass rates.
Age Concern chairperson Angela Scott said the fact these older divers were referred to take a test showed there "probably was a problem" with their driving ability.
"For a doctor to make that call is a very sensible choice because it means older people and other drivers remain safe on the road.
"Their tests check their eyesight and balance and reaction times, so I think it's good to have a qualified person to help an older driver make the decision whether they're fit to drive or not."
Mrs Scott said it was difficult when older drivers lost their ability to drive, as they could lose their independence and mobility.
Currently, drivers must renew their licence at age 75, 80, and then every two years after that. To renew their licence, drivers must obtain a medical certificate from their GP following a health and vision check.
Following this, they are classified into one of five categories: medically fit to drive without restrictions; medically fit to drive with conditions; medically fit to drive subject to passing an on-road safety test; medically fit to drive subject to confirmation by a specialist; and not fit to drive - in which case the driver's licence expires on their next birthday.
Coastal Bay of Plenty and Districts Grey Power president Ruth Dekker said current testing for older drivers was adequate.
She said most older drivers were safe on the roads, and those who weren't usually stopped driving voluntarily.
As well as the on-road safety tests, Age Concern hosts driver refresher courses where they go over the road rules and offer tips to keep older drivers safe and avoid situations that compromised their safety, Mrs Scott said.
Nationally, more than 5000 licensed drivers on New Zealand roads are currently in their 90s, with 11 aged over 100. New Zealand's oldest motorist is an impressive 104.
Around the country, nearly half the 699 drivers who underwent on-road safety tests this year have failed.
Automobile Association spokesman Mike Noon said it was desirable to keep older motorists driving as long as they could do so safely. He said that some conditions could be imposed on older drivers, which might include only driving within a certain distance of their home, or between certain hours - to keep them away from heavy traffic.
Many older drivers stopped driving at night as it was harder for them to see and lights became dazzling, he said.
They also avoided driving in heavy traffic, or around schools during busy times. Figures from the Ministry of Transport show 18 drivers aged 75 or older have been killed in crashes this year.
In the first six months of 2012, there were 12 fatal, 49 serious, and 241 minor injury crashes involving older drivers.