Wellington, March 10 NZPA - The days of affordable fuel are coming to an end and the Government needs to rein in its spending on roading infrastructure and target alternative transport, the Green Party says.

Following another large spike in the price of petrol and diesel, Greens co-leader Russel Norman said a commitment by the Government to spend an additional $21 billion on roading infrastructure after 2012 was irresponsible when only $0.7b was tagged for alternatives.

It now costs up to $1.83 for a litre of 91 unleaded petrol and $1.16 for diesel, which is the highest in 18 months and a level which AA PetrolWatch spokesman Mark Stockdale described today as an "uncomfortable price point".

Dr Norman said investment in roading, compared to alternatives such as light rail and bus lanes, was way out of kilter.

"Such a one-sided investment approach to managing our future mobility is economic mismanagement. There is no other way to describe it.

"For the person on the street, this will mean they'll have next to no alternative options for getting to work when oil prices become unaffordable for everyday transport. And this could happen very soon."

Dr Norman said a Shell head had this week said that the days of cheap oil appeared to be over.

He said the Government appeared to be putting its faith in the continued development of electric cars.

"But the new cars are expensive, their uptake will be slow, and they don't solve the problem of congestion or where the power will come from."