Prime Minister John Key says it would be more costly to send back luxury BMWs purchased for the crown limo fleet than keep them.

The Government is stuck with the contract for 34 new $200,000 BMWs and would otherwise be shopping around, Finance Minister Bill English says.

Key revealed this afternoon that the Government was not kept in the loop about the decision. A six-year deal for the cars was signed by Labour with a three-year rollover clause.

"That decision to invoke that rollover and bring new cars in was made by the Department of Internal Affairs without reference either to their minister or to me," he said.

Mr Key found out about the new cars when one of the drivers told him last week.

The department did not think it had to check as it had authority from the former Labour Government.

"I can't take responsibility for a contract that was entered into by the previous Labour Government, that wasn't bought to my attention or to my ministers' attention," Mr Key said.

"I am surprised, I would've thought they (Internal Affairs) would have referenced it to us... politically we should have known about it, we didn't."

He said Internal Affairs did understand sensitivities about spending but felt they got a good deal.

Mr Key said it was too late to say whether his Government would have approved the purchase or not and the cars were due to arrive in New Zealand soon. They would not be returned because of the high cost that would incur.

The Internal Affairs Department says it has been three years since the Government bought its last fleet, which will be sold when the new cars start to arrive later this year.

Answering questions about the purchase today Mr Key said officials from Internal Affairs had made the decision to renew some cars in the fleet without reference to Government Ministers.

A spokesman for Internal Affairs said there was no requirement to inform the Government about its decision to chose the option of buying new vehicles.

"It's our contract, we administer it. Our assessment was it was the best value for money to replace the vehicles now and we got a good deal in the first place and we got a good deal now," he said.

Had the cars been kept they would have lost value and the resale price would be considerably lower.

"The gap between the price of a new car and a second-hand one selling is greater so you are actually losing more money."

The value of the cars being sold was close to their purchase price and the Department said the contract offered the lowest annual operating costs of comparable cars due to fuel efficiency and tyre costs.

If they had decided to keep the cars and not buy new ones there would have been no penalty.

Earlier, Finance Minister Bill English when the contract came up for renewal the Government would see if there was a better deal and probably a "more mainstream model of car".

The 730Ld BMWs are not yet available in New Zealand, but the 730d models in the current VIP fleet sell for $203,500. The cars are for transporting ministers, their guests, the leader of the Opposition and occasionally judges.

The Green Party has called the ordering of the cars a disgrace.

Mr English said the Government was stuck with the contract and when it expired they would go to the market and find a more mainstream cheaper model car.

''I don't think a Government in the current recession would decide to pick a luxury brand car with all those extra bits that you're talking about whatever the value for money I think you'd go for a plain vanilla model,'' he told Radio New Zealand.

''The electorate always thinks the politicians are pampered, overpaid and far too well looked after I don't think that's going to change.''

He said he did not know about any of the additional extras in the new cars.

The options include:

- Four-zone air conditioning so the driver, front and rear passengers can set their own individual temperature, air volume and distribution.

- Massage function for front seats: "Twelve massage bubbles and six rotation bubbles help to relax the occupant's thorax, shoulder and lumbar spine". Active seats are available, which move intermittently to mobilise occupants' muscles.

- Sixteen high-performance speakers.

- Monitors and DVD players in rear seats.

- Driver-recognition means there is no need for keys.

- Automatic door-closing shuts the doors mechanically for the last 6mm.

- A built-in internet portal allows access to emails and internet.

- If you lock yourself out or are not sure you have locked the car, the BMW call centre can fix this for you remotely.

Source: BMW

Tom Hunt and Kate Chapman with NZPA