At least one Tauranga restaurant has been risking a $20,000 fine by using gas as workers try to fix the country's damaged main pipeline.
The business has been disobeying a legal order to stop using gas after the pipe ruptured.
Others are allowed to use some gas and some have been using barbecues to cook food.
Thousands of businesses throughout the upper North Island have been left without gas this week and warned not to use any or asked to curtail their use after the leak was discovered on Tuesday.
Vector is working to repair the damaged pipe in Taranaki, but local restaurants have suffered.
One Tauranga restaurant owner, who spoke on the condition they were not named, said his restaurant was still using their gas despite being told not to.
"It's our business. If we don't we won't survive," he said.
The man said he suspected many other restaurants were doing likewise, but not necessarily admitting to it.
"We won't get compensation. We aren't a big player. We have all been contacted but like I say, if we don't use it we are stuffed. We can't do barbecue with our food. For certain dishes we need a naked flame."
Alan Sciascia, regional manager of the Hospitality Association of New Zealand, said the situation had created a nightmare for restaurants instructed to not use any gas while others were told to limit their usage by gas providers.
"The direction given to them by providers is covered by legislation. To disobey that could result in a fine of up to $20,000, if you fail to follow that directive," Mr Sciascia said. "This puts the retailers in a huge dilemma. Do they risk a fine of up to $20,000 and be able to serve their customers or do they follow it and know for sure they will lose money?
"They still have to pay rent and employees even if they can't get customers through the door."
At Tauranga's Harbourside Restaurant, chefs have been cooking meals from barbecues and traditional electric ovens brought in to replace the usual gas elements.
New owner Peter Ward said the award-winning restaurant had been hugely affected by the gas outage.
"Luckily we managed to get hold of some hot plates and we are just running off gas barbecues," he said.
"We are using old electric elements and things. It's making it hard for the kitchen boys. It's really, really hard for these guys in there. They are working in pretty tough conditions."
The restaurant was forced to close for business for Wednesday's lunch before they managed to bring in alternatives means of cooking food.
Mr Ward said although their ability to function was at 50 per cent they still managed to honour their bookings.
He was disappointed to learn of other restaurants who were still using gas despite instructions not to. The continued use of the gas is understood to potentially create air bubbles in the line, which could cause further damage and result in gas being entirely out for much longer than a few days, Mr Ward said.
Spuntino is allowed to use a limited amount of gas and manager Tamsin Crilley said they had a panic moment on Wednesday, but were now "very optimistic".
"For us it was looking dire ... the initial thing was that we had to shut down, they weren't sure whatever was left was enough for everyone," Ms Crilley said.
"But we know they are able to sideline the gas a bit and let more gas through, that's why we have been asked to minimise our usage."
Jack Hogg from Bravo, which is also allowed to use gas, said they were still operating, but were "very diligent" about their gas usage.
"All chefs waste gas. It's a fact. So I've told them to turn the bloody things off. Now we only turn the stoves on when there is an order," he said.
Large food chains were also feeling the effect.
Burger King reopened last night after being closed since Tuesday.
Other industries were also suffering.
Dairy farms have had to dump huge amounts of milk after Fonterra was forced to close down processing sites.
In other parts of New Zealand, bodies were being returned to grieving families because gas-run crematoria were not able to operate.
However, Tauranga Crematorium was not affected by the gas leak as it runs on diesel.
Many shops, cafes and restaurants were allowed to use gas again from yesterday afternoon, but some larger businesses will have to wait, with repairs on the Maui pipeline leak due to continue over the weekend.
The Maui pipeline, along with a Vector pipeline that runs alongside but carries a tenth of the volume, supplies gas to nearly every centre north of New Plymouth, including Gisborne, Tauranga and Auckland.