Extinction Rebellion Ōtautahi are protesting the council's plans to build a new international airport at Tarras in Central Otago.
Wearing shirts emblazoned with 'climate emergency' and with signs saying 'Silenced!', 'Excluded!' and 'Greedsters!', they voiced opposition to the plans.
They claim that decisions are being made behind closed doors and have major fears over the airport's impact on the environment and carbon footprint.
The group urged the councilors to vote against the airport plans.
They then asked for 30-seconds of silence to "grieve the loss of democracy and transparency" at the council.