Parliament's health select committee has ticked off the bill to ban BZP-based party pills and recommended that it be passed.
BZP (benzylpiperazine) is the active ingredient in most party pills.
The bill was introduced in September, and drew many submissions when it was sent to the select committeefor public input.
The select committee's recommendation was supported by a majority of its members.
The Green Party and the Maori Party disagreed with the recommendation and put in minority reports.
The Greens said the bill was "politically expedient, rushed, knee-jerk legislation" which might increase rather than reduce the harm associated with party pills.
"It will enable some MPs and the media to table thump about being `harsh on drugs' but in our view it is likely to result in many people switching to more harmful, illegal risky drugs like ecstasy and methamphetamine and new generation party pills," the Greens said.
The Maori Party said it did not agree that banning the pills was the best way to reduce their use and minimise harmful effects.
"The Maori Party considers that a strictly enforced, strongly regulated regime, with monitoring of resultant use and harm levels, is a better first step than prohibition," it said.
The bill will now go back on Parliament's agenda for its second reading.
After it has passed that, it will still have to go through its committee and third reading stages before it becomes law.
Since the bill was introduced there have been reports that some manufacturers are trying to beat a ban by using alternative chemicals.
Earlier this month a man who tested a "new generation" party pill ended up in hospital after taking two of them.
He had taken part in a trial of non-BZP pills for Auckland company London Underground.
He said he felt he was going to die when his heart was hit by a surge of adrenaline that almost doubled his blood pressure.
