Green MP Chloe Swarbrick will need most of Labour's MPs to swing behind her alcohol harm reduction bill, if it is to pass its first hurdle in Parliament.
The member's bill would ban alcohol sponsorship in sports and give local councils the power to control liquor sales, trading hours and locations.
It will be put to a conscience vote but with National and ACT block-voting against it, its success will be up to Labour's caucus.
Political reporter Anneke Smith filed this report.