The price of petrol is heading up, once again.

The price per litre has increased 11c in just under a fortnight, to $1.88 for 91 octane.

The rises have been attributed to the increasing cost of refining crude over the same period.

Industry watchdogs are expecting the price to remain at the present level in the short term.

A barrel of petrol is now costing more than $NZ82.