A $26 million catch-up measles campaign targeted at 300,000 at-risk young adults has hit just 7 per cent of its target.

The low success rate comes as childhood vaccination rates plummet to record low levels - including for measles - which experts fear will fuel deadly new epidemics as international travel ramps up.

In July 2020, off the back of a devastating measles outbreak that saw 800 people hospitalised, the Government launched a targeted immunisation catch-up campaign to reach an estimated 300,000 unvaccinated 15 to 30-year-olds.

There were about 400,000 measles, mumps and rubella (MMR) vaccines made available and $40m allocated for the rollout (this was later revised to $26m).

The rollout was hampered by the Covid-19 response and in March last year district health boards were directed to refocus on the pandemic and other areas. It was supposed to resume in November and run until the end of June.

At the time it was paused just over 20,000 of those vaccines had been administered.

Figures provided to National Party health spokesman Dr Shane Reti show after it officially ended in June just 23,595 doses had been administered, or 7 per cent of the target.

This low success rate has also seen $8m worth of vaccines - 320,000 in total - destroyed.

Figures also show while the campaign had funds devoted to ensure it was equitable, those living in more isolated areas fared the worst.

Just 28 Māori aged 15-29 were vaccinated during the programme in Tairāwhiti, or 2 per cent of an estimated target group of 1200 (based on Ministry of Health estimates that about a fifth of people in that age bracket nationally are not protected from measles).

Reti said the results were "dismal".

"Even more shocking is the vaccination rate for Maōri in places like Tairāwhiti, which is considered a high risk area.

"This programme was doomed to fail from the start with promotional material taking three months to arrive and the Government forced to destroy $8m worth of expired measles vaccine due to the poor uptake."

Reti said Health Minister Andrew Little had "failed to deliver".

It comes after the Herald reported this week health experts were "petrified" of new deadly epidemics with child vaccination rates plummeting since the start of the pandemic.

Little's office did not respond to requests for comment by deadline.

Responding to questions from Reti in the House this week, Little said the Government had recognised existing inequities.

"It would be a failure if this country doesn't recognise that we have to do better when it comes to equity performance in our health system.

"That's why this Government has fronted up and we've established Te Aka Whai Ora, the Māori Health Authority, something that that member and his party deeply opposes."

He called on Reti to back Te Aka Whai Ora, the Māori Health Authority, "which that member and his party has opposed throughout".

"The reality is the equity performance of our health system when it comes to even childhood immunisations has been woeful, and we need Māori leadership where it counts in the health system, and now we will have it with Te Aka Whai Ora, the Māori Health Authority."

- Michael Neilson, NZ Herald