The expert group in charge of giving advice around the Meningococcal meningitis outbreak in Northland were unaware a second supplier could have provided enough vaccines to cover all people under 20 in the region.
Today, the Ministry of Health and Pharmac were grilled in a Parliamentary Committee investigating the outbreak.
The expert advisory group knew there were 20,000 vaccines available from one supplier, but were not told another company could supply 30,000.
National MP Shane Reti also accused Pharmac of tampering with an order to appear more responsive. This was denied by Pharmac.
He said Pharmac changed the vaccine purchase order "on the basis the process was delayed longer than it should and Pharmac was trying to make it look more quickly than they did".
"What would we gain by that?" Pharmac chief executive Sarah Fitt said, and "absolutely refuted" claims the order was changed.
She said the vaccine order was 10 times bigger than usual, an order was drafted so it would be ready to go if and when it was needed.
Dr Reti continued to question Pharmac over the accusations of changing the purchase date.
"We're telling you it didn't happen," Pharmac board chair Steve Maharey told Dr Reti. "The staff did not change the date."
"This is not the Trump hearing, we're not making this up... There is no conspiracy or cockup.
"That's something you'll have to accept. It is odd to have a chairperson running their own hearing."
Dr Reti said he accepted Pharmac's "view".
He later said in a statement "the Ministry of Health did not have any formal advice that there was additional supply, it only had 20,000 confirmed to it by Pharmac when there were thousands more available and that’s the advice it used to roll out the limited vaccination campaign".
"The programme that went ahead excluded 5-12 year olds...It was also confirmed today that there are thousands of vaccines left over."
Dr Reti on Sunday claimed authorities led the public to believe there were not enough vaccines available after an outbreak of deadly Meningococcal disease saw Northland families queue for hours to have their children vaccinated.
Only children under five years old and teenagers got the Government-funded jab - a shortage of vaccines one of the reasons given.
However, 1 NEWS revealed there was enough supplies of the vaccine available to cover all children in the region.
Director-General of Health Ashley Bloomfield denied that a supposed shortage was a reason not to vaccinate everyone under 20 years old.
"There had at that time been three cases elsewhere in the country and we needed to make sure we were keeping our options open," he said.
On TVNZ1's Q+A on Monday, Health Minister David Clark was asked if he was misled by health officials regarding access to vaccinations and the number available.
"I don't believe so," he said.
Dr Clark said the advice medical experts gave was that there needed to be a targeted campaign because there was a limited number of people to deliver the inoculations.
"The targeting was to stop the spread," he explained. "If you've only got a certain number of people who are able to deliver the vaccinations, you focus on the vectors, which are the teenagers...and those who are most affected, which is the young children.
"The advice was that we needed a targeted campaign, and that's what they delivered.
"By all accounts to date, it has been a very successful campaign, and I guess that is why it's important to rely on expert medical advice," Dr Clark said in the House today.