In a social media post, the couple announced with "mixed emotions and a great deal of sadness" they would be ending their lease at Queen’s Birthday weekend, June 4-6.
The post said leasing the camp, which includes 50 powered sites, 15 tent sites and 18 lodge rooms, was no longer viable and the site was no longer fit for purpose.
"Land prices mean that many camps are having to close and we have held on as long as we possibly can," the post said.
"We have propped it up for the past three years and any investment would never see a return."
The couple took over the holiday park in November 2012, after seeing the potential in the site, which had been closed and boarded up.
In 2015, they expanded their operation, taking over the Otematata Lakes Hotel, which they said in their statement would now be their main focus.
"This decision will allow us to concentrate on our hospitality operations and move forward with some exciting new developments we have planned for the pub," the post said.
"A massive thanks for all who have supported us over the years, but we simply cannot get the camp to a viable standard we can be proud of."
Mr Cowles could not be reach for comment.
The Otematata Holiday Park and Lodge is owned by Otematata Holiday Park 2003 Ltd. The sole shareholder in the company is Oamaru businessman Brian de Geest.
Mr de Geest did not respond to requests for comment on the future of the holiday park.
