The country's food safety body has expanded its testing programme for salmonella to include another 25 operations - which account for 80 per cent of eggs sold to the public.
New Zealand Food Safety (NZFS) said it believed the risk to consumers was low.
NZFS said the programme had been expanded to determine the extent of salmonella enteritidis in the country's poultry flocks, after the bacteria was detected at three farms earlier in the year.
Restrictions had been placed on those three farms, all in the North Island, to prevent potentially infected eggs from reaching consumers.
A salmonella infection can cause gastro-intestinal illness and symptoms include abdominal cramps, fever, a headache and nausea, lasting for up to 10 days.
NZFS said it had been monitoring the cases of salmonella infections in humans and found a strong association between the strain in human cases and what had been discovered on farms.
The agency had been testing 64 producers since March and was expanding the programme to 25 companies, accounting for 80 per cent of the industry's eggs.
NZFS deputy director general Vincent Arbuckle said the agency was entering the testing with "an open mind".
"While we think the overall risk to consumers is low, the extended testing is a prudent step to take on behalf of consumers," he said.
Testing would start on Monday and include taking samples from chicken sheds on each farm, he said.
Arbuckle told Newstalk ZB he didn't believe the situation would cause any egg shortages or supply chain issues.
"Based on what we've sampled to date, I think the likelihood of it causing a supply issue is low, but we really won't know that until we've finished the full survey."
The Government body was also working on a "regulatory control scheme" which would allow for better controls around the production of eggs and poultry meat in New Zealand, he said.
"We will use the survey which we are doing at the moment to help in the design of that. We're working with industry over that at present."
It would be a "couple of months" before the scheme was in place so the testing programme was a "prudent and smart thing" to do in the interim, he said.
Executive director of the Egg Producers Federation Michael Brooks said the testing programme was a precautionary measure to give the egg industry, MPI and consumers more confidence about the safety of eggs.
"This is just another step in a testing programme that we have been undertaking with MPI to ensure consumer protection," he said.
Arbuckle said consumers should put their eggs in the fridge, avoid giving raw egg to children under the age of 2, pregnant women, the frail and elderly or people with low or compromised immune systems, and cook eggs thoroughly.
"If you do those things, you'll certainly keep yourself safe."
There had been 47 cases of salmonella reported in 2021 to date and genome testing had indicated a strong association of the infections with the preparation and consumption of poultry products.