The police and Heineken, an official sponsor of next year's Rugby World Cup, are in dispute over the way beer should be served at the tournament.
Heineken wants its product to be available in cans, saying the logistics of supplying cans to the venues are simpler.
But police have made a submission to the Economic Development Ministry asking that systems be introduced at host grounds to serve beer in plastic cups.
Superintendent Grant O'Fee says that would prevent crushed cans with sharp edges being thrown.
Rugby World Cup Minister Murray McCully is due to make a decision on the issue within three months.
