The Automobile Association (AA) says that New Zealand diesel prices reached their uppermost level in 17 months in April on the support of increasing crude oil prices, and tax rises could add another 10 cents per liter to the price of petrol by the end of the year.

Retail petrol and diesel prices surged 6 cents per liter during April and 91 octane concluded the month at $1.82 per liter, and diesel at $1.22 per liter, the maximum diesel price in 17 months.

AA PetrolWatch Spokesman, Mark Stockdale, said, "At US$85 a barrel, crude oil has now reached an 18-month high and this has led to an increase in the cost of imported fuels".

Growing crude oil and refined prices were partially because of normal seasonal variations and gradually enhancing worldwide demand, particularly from Asia. Some part of the increase was made up by a small enhancement in the value of the New Zealand dollar.

Mr. Stockdale said that global market analysts anticipate that the enlarged rivalry in the refinery sector could put downward pressure on imported petrol and diesel costs in the upcoming months.

However, duties on both petrol and diesel will be raised this year. The Emissions Trading Scheme would add around 3 cents per liter to the price of both fuels from July 1, with an additional three cents per liter being levied on petrol excise in October.