Kiwi car rental company Transfercar has been hacked and its customer data compromised, according to the business.

Transfercar customers were sent an email last week alerting them to the breach which occurred on June 6.

"I am sorry to tell you that Transfercar has been the victim of a cyber security incident," the business said.

"The facility where we store our customer records has been compromised."

Advertisement

"The only information that relates to you that could possibly have been accessed by hackers would be your contact details that we pass to the rental operators when you made a booking," it said.

"Similarly the same data if you registered with us and did not make a booking."

The company said it was informing customers as part of its commitment to privacy, adding that it was "highly unlikely" they would be impacted by it.

When contacted about the breach and asked whether financial information had been accessed or if customers should be concerned, chief executive Brian Karlson said he couldn't comment.

In its email the company said it had immediately taken measures to review data security at the facility and increase its oversight.

It is not clear how many customers may have been affected and what personal information may have been accessed.

Transfercar was co-founded by Karlson in 2008. The platform was created so drivers could search for rental cars that needed relocating.

Tourists travelling to New Zealand often start in the North Island and drive South, usually leaving the cars or campervans on the wrong island Karlson said earlier.

Transfercar lets customers rent the vehicles for free to return them to the right location.

Exact terms are up to the rental companies who may tack on a facility fee or other small charges.