Winston Peters has accused National of playing "silly politics" by announcing their own medicinal cannabis bill in opposition to the Government's today.

A lengthy exchange during Parliamentary Question Time saw Simon Bridges and the Acting Prime Minister at odds over the rival bills.

"Does he believe New Zealand should implement a comprehensive medicinal cannabis regime that would widen access to medicinal cannabis and licence high quality domestic production," Mr Bridges asked Mr Peters.

The Acting Prime Minister was quick to denigrate the timing of the National Party's new bill in his answer.

"The Government's view is that if the other members of Parliament were serious in this matter then they would not have put in a private members bill that might not be drawn in favour of the Government's bill.

"Also, they would in the last nine years have shown their integrity on this issue rather than playing silly politics," Mr Peters replied.

Mr Bridges then pointed out what he said were flaws in the regulatory controls in the Government's medicinal cannabis bill.

Mr Peters replied by saying the bill was still open to amendments and called the National Party a "leaderless rabble".

Mr Bridges earlier said the Government's current bill "utterly fails" at creating the right regulatory and legislative controls alongside giving Kiwis greater medicinal cannabis access to ease suffering.

"So we will vote against it. It includes only minor improvements to how cannabidiol products are treated, which the previous National Government had already facilitated," he said in a statement.

"It is also totally silent on how a medicinal cannabis regime would operate in practice. The Government has said it will increase access now and leave it to officials to think through the controls and the consequences later."

Mr Bridges said National's member's bill, which would only go before Parliament if pulled out of the ballot, was the result of "significant work" by MPs and reflected "a blend of international best practice, tailored to New Zealand".

It proposes a licensing regime and approval for medicinal cannabis products in the way medicine is approved by Metsafe.