The accident occurred near the town of Carterton, about 150 kilometers north of the capital, Wellington.
The spokesman of health services for the district of Wairarapa, Jill Stringer, said 11 people were killed in the accident. Police confirmed that there were “many dead”.
Witnesses told local media they saw flames 10 feet high out of the basket of the balloon before it suddenly falls to the ground.
One witness said he saw the balloon and then attach a wire to try to go before crossing a road and burst into flames.
The balloon hit other damaged electrical son in his fall, causing power outages in the area for about 20 minutes, authorities said.
Police have not yet determined with certainty what caused the accident. The sky was clear and winds were light, officials said.
This region of New Zealand is famous for hot air balloon excursions are offered.