Prime Minister Jacinda Ardern says the Government is moving quickly to look into the root causes of high fuel prices.
Ms Ardern told reporters she was "hugely concerned" by rising fuel prices across the country, and that she believes consumers are being "fleeced".
She says her government is now taking steps to look into how and why petrol prices have risen so quickly, jumping up by an average of 39 cents between the end of October last year and September 28 this year.
The primary measure underway is the Commerce Amendment Bill, which is now at Select Committee stage, and Ms Ardern says it is likely to be passed within two weeks.
The Bill updates the Commerce Act to give the Commerce Commission stronger powers, including the ability to force companies to provide commercially-sensitive information to them in order to carry out studies specifically on market competition.
"Enough is enough here - even with the Regional Fuel Tax in Auckland, you see higher pump prices in Wellington and we've got to ask questions around what is going on," Ms Ardern told TVNZ 1's Breakfast show.
After the new Bill is passed, the Commerce Commission will then be asked to investigate the New Zealand fuel market and its pricing practices thoroughly in the public's interest.
"We need to get to the source of the problem - excise [the Government's fuel tax] isn't it, because that doesn't account for the extra 39 cents [price rise] overall that we've seen in the last year.
"There are a range of options that are available, but what we want to do is make sure we get in there first and see what's happening with pricing with the fuel companies."
She said she believes one of the main issues is competition.
"If you look at Wellington, one of the biggest issues they have there is just competition," Ms Ardern said. "They don't have Gull - let's speak frankly.
"And the South Island - similar issues around being able to access fuel ... so one of the questions that's being raised is what can we do to enhance competition."
Ms Ardern also responded to criticism from National's Judith Collins, who said the Government had introduced too many taxes, leading to the higher price.
"That [nation-wide] ]excise is 3.5 cents - were talking about 39 cents [rise] that we've seen [nationally] in the last year, so yes I acknowledge excise has played a part, but a much smaller part than whats going on broadly," Ms Ardern said.
"In 2017, the last government did a piece of work - the upshot of that [was] they could not guarantee that New Zealanders were paying a reasonable price, we could not guarantee it," she said.
"Well that's not good enough - we need to go that step further - and so that's why we're changing the law.
"We moved pretty quickly when we came in - we said the Commerce Commission needed extra powers, we put a bill before Parliament, its now come back to the house and we're going to use the next two weeks to finish that process off and get the law in."
Ms Ardern yesterday said it should be acknowledged that the global price of crude oil has increased by about 30 per cent just this year.
She said dropping the current fuel excise taxes would likely lead to the fuel companies simply raising their prices and keeping the change.
"If we took off excise tomorrow, I couldn't guarantee that the fuel companies wouldn't just gobble that up and continue to charge the same amount at the pump and people would be no better off," Ms Ardern said.
"The fuel companies would just take it as pure profit ... in the mean time, we're able to invest that in making sure the roads [are safe].
"Excise only came in on the first of October, and people have been raising the issue of the fuel pump price well before that.
"I need to get to the heart of the issue and that what I'm intending to do ...there are regulatory options available, but we need to build a bit of a mandate and argument for that, [so] the first step is getting in and using the Commerce Commission to do this piece of work."