BP's move to give away an hour of free fuel could have been an attempt to butter up the public in advance of a Commerce Commission market study into the price of petrol.
Sue Chetwin told The AM Show there's some confusion about what the actual cost of petrol is due to the fact so many stations offer varying discounts.
- One hour free fuel giveaway: Auckland and Christchurch punters cause traffic gridlock
- Why petrol prices are at a six-month high
- Why fuel prices could be about to rocket for New Zealand motorists
"Not many people go and pay the actual pump price when they do go to a gas station because there are so many of these loyalty programmes, so what really is the price of petrol?
"I guess that market study is going to show that. We've had a look ourselves and we've got some real question marks about what the cost of gas actually is."
Chetwin doesn't think there will be good news in the market study when it comes out.
"You know they'll realise what's coming and it possibly isn't going to look too good for them so they're trying to show that maybe they are competitive.
"If consumers are benefiting from it in the meantime, I guess that's probably a good thing."
The Government announced the investigation in December 2018 after a volatile six months in the petrol market.
Importing conditions, an increase to fuel excise and a new regional fuel tax in Auckland all contributed to pushing the price up before it dipped again.
The national average price of petrol as of July 18 was $2.25 per litre.
It's clear that the cost is a big burden on families though, Chetwin said some of the responses to the free fuel showed how much the price impacts living costs.
"It really goes to show the haves and have-nots in this country, people saying that getting free fuel meant that they would be able to pay their power bill.
"There is a deeper and darker side to all of this."