National MP Jacqui Dean opened public submissions on the classification of BZP (benzylpiperazine) today, telling Parliament's health select committee party pills opened the door to harder drugs.
Associate Health Minister Jim Anderton announced in June he planned to ban BZP, the active ingredient in party pills.
He hopes to have the legislation passed by Christmas.
The Misuse of Drugs (Classification of BZP) Amendment Bill, introduced to Parliament in August, would make the manufacture, supply, import, export and sale of party pills illegal.
The bill would classify them as Class C1 drugs, the same category as cannabis.
Ms Dean, the National MP for Otago, strongly favoured a complete ban, saying BZP-based pills caused "severe psychosis" and the public healthcare system had to pick up the pieces when things went wrong.
"If you are prepared to put a pill in your mouth to have a good time, it lowers the threshold of what you will put into your body to have a good time," she said.
"The connection between BZP and P (methamphetamine) is reason enough to ban it completely."
Ms Dean acknowledged most of her evidence as to the effects of the pills was anecdotal.
When a party pill shop opened in Oamaru, there was an increase in vandalism, and youths on the street and adjoining cinema complex were rude to passersby, Ms Dean said.
Later the shop, which also sold pipes, closed after the owner was convicted of cannabis possession.
When questioned by Maori Party MP Tariana Turia, Ms Dean was unwilling to take the same prohibitory line on smoking cigarettes and drinking alcohol as she took on BZP.
"Alcohol and tobacco have been with our society for many, many years. BZP has only been with our society for five years," she said.
Another submitter, member of the public Curtis Nixon, told the committee that from a harm prevention standpoint, banning things wasn't the best idea.
"Prohibition does not work. You lose control of the drug. The unintended consequence is it pushes manufacture and distribution into the hands of gangs ," he said, later citing the connection between Al Capone and bootleg liquor.
Drug users consumed banned substances, occasionally coming to the attention of police as in the high profile busts of Millie Elder and Marc Ellis but largely otherwise continued regardless of the legal status of their high.
"This breeds contempt, which flows over into other legal domains, meaning youth especially lose respect for law and order and the police enforcing it," he said.
Speaking on the issue of how culturally acceptable legal drugs such as alcohol and tobacco were, Mr Nixon said at one time laudanum tinctures were popular, with even Queen Victoria being a fan of the opiate-loaded drink.
Mr Nixon supported strict regulation rather than an outright ban, and argued consistency should be applied across all drugs, from alcohol to currently banned recreational drugs to pharmaceuticals.