Last year 300 practices in New Zealand did not meet that standard and Castlecliff Health was one.
Castlecliff Health co-owner general practitioner Praveen Thadigiri said the Carson St site did not met the standards and they were not in a position to renovate it because they did not own the building or the land.
Now, Dr Thadigiri and co-owner nurse practitioner Jane Dutton will be cutting the ribbon to "a dream that once seemed impossible".
Dr Thadigiri said the ministry gave them a extension to February 2018 because it saw their plan and the potential of the new clinic.
"There was a number of boxes to tick to meet the standards.
"Jane has been in touch with companies that specialise in medical buildings and we were aware of the pitfalls - like patient flow, confidentiality and visually being able to see everyone and soundproofing were all really important," Dr Thadigiri said.
He said the cost of the project, including the land value, was $1.5 million to $1.7m.
"That has come out of our own pocket ... investors turned away after all the red tape we had to battle through."
Dr Thadigiri said when they were considering closure they had about 2400 patients and 86 per cent of those were high needs.
"We have been able to take on more patients, as the demand is still high, but we are being careful to trickle in new patients to keep up with our pace of our growth."
Ms Dutton said they will also be taking on more staff.
"At the moment we have eight staff, three admin and the rest health professionals but we will be expanding."
The 100sq m space, located on a new subdivision off Mill Rd in Whanganui, has 10 consultation rooms, one for emergency appointments, and open space for ambulance parking.
The public opening will start at 10am and people will be invited for a tour.
Mayor Hamish McDouall is expected to pop in, along with some Whanganui District Health Board members.
