Nearly 1000 emails have been sent to the price gouging complaints address since Monday - the most common complaint about the price of cauliflower.
Supermarkets are among the few essential businesses allowed to continue operating while the country is at alert level 4.
But there have been reports that some stores are taking advantage of the lockdown situation and raising prices on many goods.
In response to the claims, Prime Minister Jacinda Ardern announced on Monday the Government had set up an email for people to dob in any supermarkets they thought were guilty of the practice.
On Wednesday, Ardern told reporters 990 emails had been received.
"I do want to say to people that we are taking these complaints seriously," she said.
Ardern said in some cases it will be an issue of supply constraints - particularly with produce.
"We are investigating complaints that are made because this is a time when we want to know New Zealanders are being treated equally."
She said traders will be involved in the process and have a chance to respond to complaints.
"Again though, I urge everyone [to] shop as normal and be kind to the supermarket workers who are there so you can remain stocked up at home."
On Tuesday, Consumer NZ head of research Jessica Wilson said an email address may not be enough to stop the price-gouging problem.
"We really need some price monitoring to make sure that the prices consumers pay at the till are really fair," Wilson said.