The country's only scheduled flights to Norfolk Island will end this year.
Air Chathams said it would withdraw flights between Auckland and the Australian territory from April, highlighting weak demand and costs.
The service began in September 2019 but faced significant disruption during the Covid-19 pandemic.
"Since the pandemic, rebuilding passenger numbers on the Norfolk Island route has proven difficult, as travel costs and operational expenses have increased significantly," chief commercial officer Duane Emeny said.
"Air Chathams continues to struggle with rising costs across the sector, including the cost of aircraft parts, aviation services (airports/airways/regulation), and labour force."
The airline also highlighted New Zealand's economic slowdown and said its turboprop aircraft could not match the lower per passenger operating costs of jet aircraft that served other nearby Pacific Islands.
The airline said it requested the Norfolk Island Regional Council for extended financial support, including waiving some landing fees and marketing funds, but could not reach an agreement that allowed it to extend services beyond April.
Air Chathams said after April, any flights to Norfolk Island would be operated on a charter basis.
The Norfolk Island route was the airline's only international route.