NZ Lotteries has told retailers in its network to stop selling synthetic cannabis and party pills - products it fears could damage the Lotto brand.

"There's quite a lot of public outcry about these substances. It got to the point for me and my board that we no longer felt it was appropriate to have our brand associated with these substances," NZ Lotteries Commission chief executive Wayne Pickup said.

"There's overwhelming support from communities around New Zealand to get these off the shelves."

Of more than 1200 retailers in its network, NZ Lotteries had sent letters to about 600, predominantly dairies, requiring them to have synthetic cannabis and party pills off the shelves by July 1.

Of the 600 independently-owned retailers sent letters, probably one-in-10 or one-in-15 were selling the substances, Pickup said.

Under legislation being rushed through Parliament the legal highs industry will have to prove its products are safe before they can be sold.

Last month, then-associate health minister Peter Dunne said the psychoactive substances law needed to be in place by August 13 to take over from the temporary class drug notice regime.

The regime had banned 35 legal high substances, but the first of those bans would expire on that day.

Dunne said the drug notices had done their job, but were always a temporary solution until the legislation was in place.

Current laws were ineffective in dealing with the rapid growth in synthetic psychoactive substances, which could be tweaked to be one step ahead of controls, he said.

Products were being sold without any controls over ingredients, without testing requirements, or controls over where they could be sold.

Today Internal Affairs Minister Chris Tremain and Associate Minister of Health Todd McClay said they supported the NZ Lotteries' move.

"The sooner psychoactive substances are out of shops the better," Tremain said.

"New Zealanders are extremely concerned about what these products are doing to the health of our young people. This is a community issue and I am pleased to see Lotto making a firm stand on it.

"Selling these substances is not compatible with the sale of lotteries products."