Wellington, July 31 NZPA - Millionaire pharmaceutical businessman Sir Graeme Douglas has donated $3 million to Starship Children's Hospital to launch a new radiology MRI service.

Sir Graeme, a former Te Atatu pharmacist who established Douglas Pharmaceuticals in 1967, was knighted in the June Queen's Birthday Honours list for services to athletics and philanthropy.

He and his wife, Lady Ngaire, were yesterday announced as the donors of the largest ever personal donation to the hospital.

The $3 million would go towards launching a radiology MRI service to avoid "the delays and discomfort currently experienced by young patients", Sir Graeme said.

Previously, children needing an MRI scan had to be transported under sedation into the adult facility, which was often a frightening experience, particularly for young patients.

Having an MRI machine at Starship would mean children would be treated in the hospital's familiar and child-friendly environment.

About 2,000 children would benefit from the machine each year.

Starship Foundation chief executive Andrew Young said the donation's size was unprecedented for the charity, which was "grateful and overwhelmed" by the couple's generosity.