Some Kiwis are paying nearly $3000 a year to insure their Toyota Aqua cars, with one insurer denying cover unless the vehicle has an immobiliser.

The high price was because the Toyota Aqua is the most stolen car in the country, according to data provided to RNZ by three insurance companies.

Cove Insurance says it is simply too much of a risk without an immobiliser.

"That level of risk doesn't work for anyone - the customer having the car stolen, us as Cove or our other customers paying higher premiums to cover it.

"We wanted a solution that would allow people to keep their cover in place at a reasonable price and an immobiliser solves the issue by dramatically reducing the risk."

But that was not enough to put off drivers from buying these fuel efficient cars.

For 22-year-old software engineer Kian Jazayeri, buying a Toyota Aqua as his first car was a no-brainer.

"In Christchurch it's very flat, so it's basically the best place for the car and just one of the fuel savings that comes from it.

"I'm only filling up fuel like $80 per month or even like $80 per month-and-a-half really."

He bought it second hand for $10,000.

But what he saved in fuel, he paid for in his insurance premium

"I'm paying around $250 per month for comprehensive and theft [insurance]"

"I'm still wondering whether I should go with third party instead, just to save that money," he said.

But the data was not enough to deter Tracy and her husband from Nelson.

They bought a second hand Aqua in 2022 for $12,000, and liked it so much they decided to get another one for the same price.

But this time the couple were in for a surprise.

"The original one was a key start, the second one was push start."

When she contacted her insurance company about the new car, she was quoted a premium was a lot higher than she paid on her original Aqua.

"So then I asked them how much will my insurance be on the older car when I renew it, and it skyrocketed as well."

During the time they owned their first Aqua, the model had climbed the ranks of New Zealand's most stolen vehicle.

AA Insurance head of motor claims Beau Paparoa said the high number of claims involving Aquas affected the owners' premiums.

He said while AA insurance encouraged their customers to install security features such as immobilisers, that would not reduce the premium.

"Definitely that is one of many factors that will be built into considering what premiums we charge.

"Our premiums are calculated across a number of other factors as well.

"We take a really close look at what the full cost of claims are and we want to make sure that we're collecting enough money to be able to pay for those claims."

AMI Insurance data also showed the Toyota Aqua had been the most stolen car for two years running.

Favio Nazareno and his girlfriend bought their Aqua in 2023. Within 12 months, their insurance premium went up by nearly 25 per cent from $946 to $1180.

The insurance company told them the increase was influenced by a range of factors - including location, type of car, number and types of claims.

Nazareno said those factors had not changed in the year he owned the car.

"Nothing changed, no accidents.

"We both are drivers with full driver licence, we both are more than 30 years old and we didn't change our location."

But Paparoa said despite the theft data, the Toyota Aqua was a good buy.

"They're a pretty cool car actually, economical and the right price range for a lot of people."