The opening of a multimillion-dollar apartment complex in Christchurch will see accommodation for those in need of hospital treatment in the South Island triple.

Rānui Apartments will serve as a home away from home for those who are sick, and their families, when it opens its doors next month.

"We're always here to lend a shoulder and an ear on a tough day, and that can mean the world if someone is having a particularly tricky time," Bone Marrow Cancer Trust CEO Mandy Kennedy told 1News.

The complex, which boasts 43 furnished apartments, is located just 500 metres down the road from Christchurch Hospital.

"When you look at what this facility is for and the support it gives our wider community when they're coming to Canterbury for treatment, it's pretty special," Higgs Construction director Paul Harris said.

Last year, the Bone Marrow Cancer Trust had to turn away 664 families from its sister site, Rānui House.

Kylie Raine and her family needed somewhere to stay when she had to get a double mastectomy a year ago.

She said having accommodation like Rānui House is "so important".

"I don’t like being away from family, I don’t like being away from my children. The fact that they could come and stay with us was amazing," she said.

"Every time I was booked in to have an operation, they would say, 'Do you need one or two rooms this time? Are the boys coming down?'"

So far, they have had five visits – all paid for.

Now, the family is part of a campaign to raise funds pushing to get the new complex open by November in the hope no one is ever turned away again.

Donations can be made via the Rānui Apartments website.