Support for the Cannabis Legalisation and Control Bill is dropping

The latest One News Colmar Brunton Poll shows only 35 per cent of respondents support the legislation.

It's a five per cent decrease from June's poll while the number of people against the bill has risen to 53 per cent.

People more likely to support the bill include Green and Labour Party voters, people aged between 18 to 29 and Maori.

Those most likely to oppose cannabis legalisation were people aged 50 and over and National Party supporters.

The referendum takes place next month.