BP and Z Energy have increased the price of petrol and diesel by 6 cents a litre in the wake of the drone attacks on Saudi oil facilities on Saturday. 

"Following drone strikes on Saudi Arabian oil production facilities over the weekend there has been a sharp increase in the barrel price. This has happened alongside a weakening of the New Zealand dollar," BP spokeswoman Leigh Taylor said.

She said BP had responded by increasing the prices of all its fuel products at BP Connect around the country by 6c on Tuesday.

"We are acutely aware of the impact of rising fuel prices on consumers and will continue to review BP Connect prices every day to ensure our pricing is as competitive as possible," she said.

Z Energy said its price rise was also nationwide and attributable to the oil price rise that followed the Saudi attacks and "foreign exchange movement".

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Spokeswoman Georgina Ball said it had initially upped its prices by 9c per litre and then decreased its price rise after "a competitor" moved by 6c.

"This is a high volume, low margin business so the decision was to make less money today to ensure we remain competitive in the market. So, for now Z is wearing the additional cost of the change in the commodity inputs. This is not sustainable long term," Ball said.

The New Zealand dollar has fallen by about 1 per cent cent over the past week, to trade around US63.3c.

Earlier on Tuesday, rival Gull promised not to increase the price of petrol at its company-controlled service stations before Saturday.

Gull New Zealand general manager David Bodger said the price of refined petrol and diesel on the Singapore exchange, which forms the benchmark for New Zealand fuel prices, rose by US$6.50 and US$5.50 a barrel, respectively, overnight.

At the current exchange rate, that implied petrol prices would need to go up 6.5 cents a litre and diesel 5.5c a litre, he said.

But Bodger said it had decided not to respond immediately.

"We are committed to not increasing before the end of this working week."

Bodger said the short-term direction of oil prices was unclear.

"It might go up again by the same amount tomorrow. But who knows."

The industry was waiting for word on the engineering assessments of the damage to the Saudi facilities, he said.

"If it is a few hundred metres of pipe that is simple.

"If it is 20 bulk tanks and a few kilometres of pipe and it is all still quite 'warm' and you haven't quite put the fires out, then it is bloody hard."

Mobil has also been approached for comment.