The operator of the Tui offshore Taranaki oil and gas field says probable reserves are between nine and 11 million barrels of oil short of the 50.5 million barrels previously thought.

Budget documents reveal a power cable to the Kupe gas and oil field has failed and is the subject of a $95 million insurance claim.

Petrol prices are likely to keep climbing past this week's record highs, despite a sudden drop in crude prices yesterday.

Motorists should expect to see a drop in the cost of filling up their cars early next week.