National Public Health Service (NPHS) medical officer of health Dr Matt Reid said HNZ was aware of "a number of people" from around the country who attended the festival who had been in contact with people now known to have mpox, previously known as monkeypox.
Queenstown’s 21st Winter Pride Festival ran for 11 days and attracted thousands of people to the resort town.
NPHS was investigating and along with sexual health services providers was giving support to those identified through contact tracing, Dr Reid said.
No new cases had been confirmed, he said.
NPHS was working with New Zealand’s national HIV prevention and healthcare organisation, the Burnett Foundation, and sexual health services to promote prevention and manage the risk from mpox, he said.
"Mpox is a rare infection and the risk of it spreading widely in New Zealand remains low," he said.
"NPHS remains well prepared to manage mpox cases and is continuing to closely monitor the international situation.
"NPHS has sufficient capacity to provide protection and treatment."
The World Health Organisation (WHO) last month declared mpox a global public health emergency for the second time in two years, after an outbreak of the viral infection in the Democratic Republic of Congo spread to neighbouring countries.
"Most people fully recover, but some get very sick."
Dr Reid said there were two types of mpox — known as clade I and clade II.
Both have caused the ongoing outbreaks in African countries, but the Democratic Republic of Congo outbreak is linked to clade I.
To date there were no cases of clade I in New Zealand, or in neighbouring countries, Dr Reid said.
Mpox clade II was the most common type worldwide and every case identified in New Zealand to date had been that strain of the disease.
"New Zealand’s response to mpox to date has involved a range of activities, including contact tracing and support, testing and treatment, prevention activities, and mpox consultations where appropriate.
"If you think you may have been exposed to mpox or if you develop symptoms, especially a rash, you should stay home and seek medical advice.
"You can contact your nearest sexual health clinic, your GP, or Healthline."
The HNZ website said the fatality ratio for clade I was as high as 10% but for clade II it was about 1%.
Dr Reid said NPHS was continuing to update mpox clinical advice for healthcare professionals and information to the public and engaging with the organisers of the Winter Pride festival to promote public health advice.
Festival co-directors Sam Coulthard and Odette Rose said they were following the advice of both the Burnett Foundation and the United States’ Centres for Disease Control and Prevention (CDC).
"We are advising any guests who show symptoms to seek early treatment and to follow the advice of their healthcare team.
"We are asking for everyone to help us contain this outbreak."
Burnett Foundation chief executive Joe Rich told RNZ anyone who attended Winter Pride but was not symptomatic did not need to worry unless symptoms developed, or they had been notified by somebody as a contact.
"In New Zealand, gay, bisexual men and other men who have sex with men are at the greatest risk," he said.
"That’s where we’ve seen previous outbreaks spreading and the ones that are circulating in Australia are the same."
