By Rowan Quinn, RNZ

Auckland health authorities are urgently recruiting more contact tracers as the national system hits capacity just five days into the outbreak.

The tracers are vital to the Covid-19 response because they get people who have been in contact with the virus isolated before they can infect others.

Laboratories, testing sites and vaccination centres are also straining at the seams as the health system struggles to keep pace with the Delta incursion.

Director general of health Dr Ashley Bloomfield said the country's contact tracing system was working at 100 per cent, with its Covid surge plan in full use.

Auckland, home to the vast majority of the 8667 contacts identified so far, is now looking for more tracers.

Auckland University public health lecturer Colin Tukuitonga is working with Auckland Regional Public Health to help find them.

It was an illustration of the pressure the system was under, he said.

Pre-Delta, many of those who attended large gatherings would have been considered casual contacts but the infectious strain had taken tracing to a new level and the sheer numbers meant everything took longer, he said.

"Every single individual who's on the list of contacts needs to be contacted and their situation ascertained and explored and investigated to see what sort of risks they're under," he said.

The work was incredibly demanding and the teams were doing a tremendous job, he said.

Tukuitonga was particularly hoping to find skilled Pacific tracers for the new Samoan Assembly of God location of interest in Māngere.

More needed to be trained long term - from all of Auckland's diverse backgrounds - but that took time, he said.