Plunket is pulling out of its long running car seat rental service.

The charity says hiring out car seats is no longer profitable, and it will phase out the services over the next 12 to 18 months.

Thousands of parents have been renting or buying car seats from the charity since 1981.

But chief operating officer Andrea McLeod says most people now buy or hire their child restraints from retailers.

"It's running at a loss, and as a charity we really can't afford to sustain this part of our business."

Andrew McLeod says most parents are now buying their own child restraints, and the end of its car seat rental service is simply a sign of the times.

"People are much more likely to buy a car seat than hire one" that there were in 1981, she says.

"There are many more retailers selling car seats."

The service will be closed in major centres, and gradually replaced by other retailers and organisations in smaller communities.

When the service was launched, the charity’s research found only around 20 percent of children were properly restrained when travelling in cars.

Research by the Ministry of Transport last year found 93 percent of children under five travel in car seats.

Plunket plans to focus instead on helping to prevent children from being injured in the home, where most injuries to children now occur.