It is essentially a holding classification before those drugs are then made Class A.
Conviction under the Misuse of Drugs Act for making, importing or supplying Class A drugs attracts a maximum penalty of life in prison.
The introduction of the Bill today follows the Coroner revising up the number of deaths attributed to synthetics.
In November it was 45-50 since June 2017 but has jumped to 60-65 with potentially more.
A spokesperson for Coronial Services said there were seven confirmed deaths from synthetic cannabis toxicity and around 55 cases that appeared to be linked.
"There are also a number of deaths where, while synthetic cannabis contributed to the death, synthetic cannabis toxicity was not the ultimate cause of death," the spokesperson said.
When Clark and Nash announced the detail of the Bill in December, $16.6 million was also announced to boost community addiction treatment services, including $8m over two years to develop a multi-agency drug early warning system.
But Drug Foundation executive director Ross Bell said little action had materialised so far.
"The lack of action and urgency from government departments continues to frustrate.
These systems have existed in Europe for 20 years. This is not rocket science," Bell told the Herald last week.
The system has been proposed to work in the same way as Operation Bates, a multi-agency operation that swung into action in Porirua and the Greater Wellington area in late 2016 and early 2017 when there was a spike in callouts to emergency services for people who had consumed synthetics.
Bell said if a drug early warning system had been up and running when it was meant to have been, "the synthetics crisis that we experienced when those first drugs had been identified at the border, even before they made their way on to the street, we would have been in a position to act".