A word of warning that petrol prices will rise eventually, and we shouldn't make too many long term decisions while it's cheap.

Massey University's Professor of Sustainable Energy Ralph Sims says the supply of petrol is staying the same, even amid the sudden dip in price.

He says that will only contribute to the price rising again.

"The short term thinking is, 'well, this is great', but we've got to look towards the longer term and think of the repercussions of when it does go up again."

Sims says the current dip in fuel prices is only temporary, and puts off the discovery of alternatives.

"It does mean that we're going to produce more greenhouse gasses and it does mean also that going to electric cars and electric motorbikes etcetera might get pushed back a bit."