KEY POINTS:
Petrol companies had no choice but to raise prices after the international price of petrol climbed last week, says the Automobile Association.
The four main petrol companies increased their price of petrol at the pump by five cents a litre yesterday afternoon.
Caltex, BP, Shell and Mobil are
now selling 91 Unleaded for 137.9 cents a litre and 95 for 142.9, although BP is selling 95 for 143.9.
Gull was yesterday the only petrol company to hold out on price rises and is selling 91 Unleaded for 131.9 cents a litre.
But AA policy analyst Mark Stockdale said the price rises by the big petrol companies were justified.
Mr Stockdale said the international price of petrol rose last week, resulting in a fall in margins for petrol companies.
"They haven't adjusted the price of diesel because the [diesel] margin is a little higher," Mr Stockdale said.
He said the weakening of the New Zealand dollar has also caused difficulties because petrol and diesel is traded in US dollars.
"Oil companies work on the basis of a one week lag and they haven't been able to hold out any longer," Mr Stockdale said.
Yesterday, Shell spokeswoman Jackie Maitland said supply had been constrained with the refinery in Whangarei closed for temporary maintenance.
She also warned that the 4 cent drop in the New Zealand dollar so far this week had not helped prices going into the future.
Mobil spokesman Alan Bailey said the rise followed a "significant increase" in the regional market price for petrol in US dollars against a weakening New Zealand dollar.
The New Zealand dollar has continued to fall, slipping below 54 cents against the US dollar overnight.
It has recovered slightly since and at 8am this morning was buying US54.02c having dropped from US55.60c at 5pm yesterday.
Caltex spokeswoman Caroline Bland also pointed to the weakening Kiwi.
She said pricing staff had told her that last week's average for the dollar was around 59.45 cents against the US dollar but this week it had gone down to 57.45 cents.
Gull's regional business manager Dave Bodger said Gull would be reviewing its prices today but said diesel could fall in price.
Shell
91 Unleaded: 137.9 cents a litre
V Power: 142.9
Mobil
91 Unleaded: 137.9 cents a litre
95 Ultra: 142.9 cents a litre
Caltex
91: 137.9 cents a litre
95: 142.9 cents a litre
Diesel: 103.9 cents a litre
BP
91 Unleaded: 137.9 cents a litre
95: 143.9 cents a litre
Diesel: 103.9 cents a litre
Gull
91: 131.9 cents a litre*
Regular Plus - a biofuel blend: 129.9
*Lower at some sites.