National has been the first to deny the Greens cross-party support for its new cannabis reform bill.

Nandor Tanczos has proposed a bill which he says meets everyone's concerns about decriminalising the drug.

The bill would introduce a system of fines for cannabis possession, along the same lines as current speeding tickets.

However, National families' spokeswoman Judith Collins says the bill sends a false message that cannabis is harmless.

She says her party does not plan to see more New Zealand children exposed to drugs.

She says the only cross-party support the bill has is with Labour but adds even then, many in Labour would not agree with this move.

United Future leader Peter Dunne has also come out against the new bill.