"So to avoid a nasty fine - it's recommended that you do some homework on where you can and can't sleep."
Wilson said: "I can't think of a worse way to portray the country.
"To compare the Government to crack dealers; I'm sorry, at what point is this OK?"
Instead, the company should be telling its clients why they were being asked to park in camping grounds in many parts of the country.
She described the advertising on the site as misleading and "very, very offensive".
Wilson also said Wicked Campers was part of the problem with freedom campers in New Zealand.
She said the reason the company's vans were cheap was because they were "uncertified", or did not have toilets.
The Government needed to tell the company "this isn't OK that you continue to do this".
"It is not OK to send them out on the streets or roads of any part of this country saying 'you can just defecate'."
Wicked Campers did not respond to a request for comment.