A sex education trial backed by ACC is set to become mainstream.

The "Mates and Dates" initiative was piloted in eight secondary schools in 2014 after the Roast Busters scandal.

It will be rolled out at schools across the country at a cost of $18 million.

Under the programme, external educators will be brought in to teach students in years nine to 13, with each student having access to five lessons.

But this programme is getting criticisms from the Sexuality and Health Education Experts Group.

Group spokesperson and University of Auckland professor Katie Fitzpatrick told Larry Williams that the issue for them is the amount of funding going into this programme, when teachers are not allowed.

“They are the best people to do it. They are trained, they have the skills and the knowledge. ACC has decided instead to find outside providers, people who are in the community, and spending $18 million on that is an awful waste of public money.”

She says it’s debatable whether or not ACC should be involved in this programme.

ACC is standing by the programme, telling ZB earlier that it is confident the healthy relationships programme it's rolling out in schools is well put-together and worth the money.

It says Mates and Dates is well-researched, and its pilot in schools was positively received.

ACC spokesman, Mike McCarthy, says there's evidence showing having experts teaching the programme initially is best, with a view of getting teachers to run it in the long term.

"In time, up skill our educators who may not feel comfortable dealing with this particular aspect is a very complex issue, though. We don't want to create any harm."

LISTEN TO KATIE FITZPATRICK TALK WITH LARRY WILLIAMS ABOVE