"In addition to this, we are experiencing high losses and we are unable to sustain the business in this manner."
The letter to staff added it would "honour all our commitments stipulated in the employment agreements" and staff would be "compensated" for the Monday-Thursday shifts that had previously been rostered up until July 2.
It ended stating: "We are aware this is an unsettling time for staff. We appreciate your support during this period."
One staff member said that for the past year the resort - a family favourite for Kiwis and also for overseas visitors - had "gone downhill".
She feared the pending changes - coming ahead of the upcoming school holidays - would impact on up to 40 fulltime employers, as well as "a lot" of casual staff members.
Another staff member said she had decided to leave Waiwera Thermal Resort as she had "had enough".
She feared life guards, cleaners, cafe workers and office staff could lose their jobs.
Avi Jayapuram, the general manager of Waiwera Water denied there would be job cuts.
"Sorry? You are wrong." He said. Call me back in five minutes". Jayapuram, never returned any more calls.
A posting on the resort's Facebook page states the location is set to go under an "exciting refurbishment".
As well as notifying customers about the change in operating hours, it says "we will honour our commitments to any current memberships once we have reponed or refunds will be available to be claimed if that is preferred."
Khimic - an oil mogul who used to be a top executive and part-owner of Russian oil company Naftasib - took full ownership of the Waiwera Thermal Resort in 2011.
He has previously told the Herald that resort was "fundamentally an excellent facility with great potential".
Previous plans mooted for Khimic's holdings in the area included transforming an old camping ground into a five-star lodge with spas, villas and apartments.