Moore said they had decided to refurbish the hospital's older bedrooms that were now being used more often.
"I think a big part of it is we're doing a growing amount of surgery on behalf of the regional DHBs [District Health Boards] including the Lakes, Waikato and the Bay of Plenty.
He said the private sector was an important complementary part of the health system.
"A significant part of surgery is done in the private sector. It's vital there's a vibrant and modern, healthy private sector."
The expansion and alteration project was expected to be completed some time this year.
Rotorua branch president of the Registered Master Builders Association, Martin Dobbe, said they had "strong books" heading into the New Year.
"A lot of our builders have been busy," he said. "We're coming back to good amounts of inquiry and work."
Dobbe put the busyness down to confidence and people were starting to plan ahead.
"Most people will be confident about what the year is going to bring and looking to hire staff and secure key people such as builders and tighten trade relationships."
Rotorua Chamber of Commerce chief executive Bryce Heard said more houses were needed and the opportunity to get government funding for commercial buildings had never been better.
"I'd say we're in for a pretty good year building wise," he said. "The builders I know have been flat tack."
The latest Stats NZ data showed there were 2001 new dwellings consented in the Bay of Plenty in the year to November 2020. That included 159 in November alone.
December's top 5 building consents
58 Otonga Rd Southern Cross Hospitals Limited Stage 1 - extension and alterations to ward 2 Issued: December 2 $3,350,000