Sexual health experts say an ACC education programme is a waste of money and it won't reduce sexual violence rates for Māori.
Te Whāriki Takapou is "appalled" by a decision to spend more than $18 million on the Mates and Dates programme - instead of investing in schools directly.
And teachers and researchers say the controversial national programme, which involved outside providers giving students sexual health education, doesn't align with the curriculum.
Last week ACC announced the programme would receive $18 million to provide sex education for high school aged students.
The programme sees year 9 to 13 students attend five 50 minutes sessions over five weeks of the school year.
Te Whāriki Takapou chief executive Allison Green said she was shocked at cost of the programme.
"We think it's an appalling spend and irresponsible of the government - we think that ACC has jumped the gun actually."
A report this month from the United Nations Committee for the Elimination of Discrimination Against Women showed Māori under-report family and sexual violence.
And Ms Green doesn't believe this programme will help to improve these statistics.
"Less than 9 percent of Māori report sexual violence to the police so from our perspective it's critical that we have programmes that are evidence based."
Te Whāriki Takapou spends $100,000 a year on research and producing evidence based programmes for Māori students between year 7 and year 9.
Ms Green said the sexuality and reproductive health promotion organisation, hasn't had an increase in its budget since the 1990s.
"So we spend half of our contract working with Kura Kaupapa Māori and Wharekura to develop teacher led sexuality education programmes underpinned by Matuaranga Māori and for delivery in Māori medium schools."
Auckland University associate professor Katie Fitzpatrick was the lead writer for sexuality education guidelines used in schools since 2015.
Dr Fitzpatrick told RNZ that the controversial national programme is taught by groups outside schools.
"The programme itself is five lessons - so it's not really a lot of time it doesn't allow for a lot of depth or ongoing discussion - the sexuality guidelines recommend 12 to 15 hours per year so five lessons a week doesn't really cut it."
Dr Fitzpatrick said the programme goes against international best practice which shows teachers should lead sexuality education.
"There are teachers who have sloughed away themselves for years to create excellent programmes with no new funding, resources and support or professional development."
Allison Green wants the funding for the Mates and Dates programme to be pulled and used more effectively.
Ms Green said experts in the area need to come together to decide how the funding would best serve sex education in schools.
"There's very little money spent even in english medium schools to support and resource teachers to deliver evidence based sexuality education in schools."
However, ACC injury prevention portfolio manager Mike McCarthy said the programme has been a success with recent independent evaluations showing 62 percent of all young people found it good or excellent, while 28 percent of students found it ok.
"It's really important to recognise Māori and Pasifika young people were actually reported the most likely that it was relevant to them and most likely they would change the behaviour as a result."
In the last four years, 37,000 students from around the country have been through the programme.
"It's a very small percentage of students that we've got to so we actually need to build our structure to work on what's next," Mr McCarthy said.
Last year, $27.4 million was spent on sensitive claims for 14-24 year olds and new claims were also up 18 percent.
"This programme itself is no silver bullet, it's not intended to be a panacea it has to be part of a comprehensive package."
Mr McCarthy said the programme had received positive feedback about how its facilitator lead approach.
"Facilitators are quite different to some of the teachers they see on a daily basis where they may actually be embarrassed to talk about this stuff.
"So [they] actually felt they were in a position to openly engage and perhaps ask questions they might not ordinarily ask."