Key Points:

The Government's new BMW limousines are not only "greener" than the cars used now - they are faster and twice the price.

The German company's diesel-powered BMW 7-Series will now ferry the Prime Minister and other dignitaries, consigning Ford and its petrol-powered Fairlanes to the scrapheap after decades of service.

BMW New Zealand beat 15 other car companies with its tender for the 34-strong fleet, which for the first time asked bidders to meet fuel consumption and emissions requirements.

Department of Internal Affairs VIP transport service manager Rex Ambler said the BMW was the most fuel efficient and second-best in emission standards.

The purchase price was not disclosed, but BMW New Zealand said a 730ld would cost the ordinary driver $170,000 - substantially more than the Ford.

Mr Ambler said the BMW "also represents excellent value for money", with much cheaper "whole-of-life" costs - everything from depreciation to daily running costs - than the Fords.

A blogger on kiwiblog.co.nz points out that the BMW's top speed of 238km/h is 20 per cent faster than the Fairlane, making it "easier to get to the rugby on time" - a reference to Helen Clark's speeding motorcade in 2004.

The BMW is named as a "green hero" in the luxury car category of the latest issue of British car magazine What Car?

The magazine said it might have "love-it-or-hate-it" looks, but is great to drive and "makes an excellent limo".

Herald motoring editor Alastair Sloane said the diesel engines would be much cleaner and more economical than the petrol-powered Fords, "which are pretty much past their use-by date from a technological point of view".

He said the BMW's emissions "made it cleaner than probably 98 per cent of the vehicles on NZ roads".

The first 13 BMWs will hit the road in June, and the rest phased in over three years.

The chauffeur-driven limousines carry the Prime Minister, the leader of the Opposition, ministers, judges and visiting heads of state and royalty.

The current fleet - recognisable by its "CR" number plates - is almost exclusively Ford.

A Ford spokeswoman said the company had not tendered as it would be discontinuing the range in New Zealand and Australia because of a lack of demand for big vehicles.

Green Party co-leader Jeanette Fitzsimons called the BMWs unnecessarily big "gas guzzlers". She could work just as hard as other MPS while driving a 1300cc car which used less than five litres of fuel for every 100km travelled.

Ms Fitzsimons said the BMW's eight litres of fuel for 100km broke the Government's Energy Efficiency Conservation Strategy, which called for diesel vehicles to use only 6.5 litres.

Climate Change Minister David Parker said the change was because the Government "walks the talk on sustainability", leading it to the German BMW.

In

BMW 730Ld
Costs about $170,000
Uses 8.1 litres of fuel (diesel) per 100km
Emits 212 grams CO2 per km
Top speed 238km/h
six cylinder, 3 litres

Out

Ford Fairlane
Costs $71,990
Uses 10.21 litres of fuel (petrol) per 100km
Emits 260 grams CO2 per km
Top speed 200km/h
six cylinder, 4 litres