Green MP Julie Anne Genter has witnessed first-hand the horrifying effects of the synthetic cannabis crisis that has claimed seven lives in the past month.

A week ago, the Auckland Issue spokesperson for the Green Party saw a man having a seizures after using synthetic cannabis, and is concerned for those addicted to the product.

Ms Genter said she and other Green Party members she was with stopped to help as the man rolled on to a busy road, and called an ambulance.

"We had to go out and stand around him basically on the street so that cars wouldn't hit him."

Ms Genter said the crisis needs urgent action from the Government.

"This particular episode and the seven deaths in Auckland in the last month are related to something new and quite dangerous that the Government needs to get on top of right now."

She said if genuine cannabis was legalised, the problem with synthetic cannabis would not be so severe.

Ms Genter would also like to see the police resourced with addiction and health specialists.