Ngai Tahu Tourism has entered into a joint venture with Earth & Sky, the Tekapo-based stargazing and observatory tours operator.
Details of the multi-million dollar 50/50 joint venture deal remain confidential.
Ngai Tahu Tourism chief executive Quinton Hall said the partnership would enhance both businesses.
"This joint venture is a great fit for Ngai Tahu Tourism and aligns with our diverse portfolio of iconic experiences in the southern region," said Hall.
Ngai Tahu Tourism is one of the largest tourism operators in New Zealand, hosting one million customers a year across nine existing businesses.
Earth & Sky's stargazing and observatory tours on the summit of Mt John are recognised as some of New Zealand's premium night-time tourist activities. The company is owned by the Murray and Ozawa families and has been built over 12 years.
Earth & Sky's owners say they are pleased to have Ngāi Tahu Tourism on board.
Owner Hide Ozawa says the focus on protecting the night sky will continue with Ngāi Tahu Tourism.
"Both businesses are committed to continuing to protect the beautiful dark environment for stargazing, scientific research and to enhance wellbeing of our people."
More than 200,000 visitors are expected to visit Earth & Sky during the coming year.