Photos of the famous skyline cover the elevator walls. For Ms Benson, who spent much of her life travelling Europe, the Big Apple remains the one city she's always wanted to visit.

"I never got to go, it's my dream, I'd love to meet a real New York policeman," she regularly tells staff at Uniting Mirinjani aged care.

"Just the idea of strolling through the streets of New York and asking a policeman for directions to the nearest coffee shop."

On Thursday, Ms Benson burst into tears when Detective Howard Shank of the New York Police Department stepped through those same elevator doors - in uniform.

"I don't know about coffee, but I can show you where all the best doughnuts are," Detective Shank told Ms Benson as he surprised her at lunch.

Ms Benson, who has dementia, said she felt about 20 years old again as she embraced the officer, and proudly modelled his blue police cap.

"I never married and I never had children but this excitement, this has been the best day of my life," she said.

The emotional surprise was more than two years in the making, says Jo Sumner, coordinator of leisure and wellness at Uniting Mirinjani.

Since Ms Benson moved from Melbourne to join her brother John and his wife Judy at the home, Ms Sumner had been searching for a way to bring her New York dream into reality.

After some detective work of her own, she asked a close friend and Australian Federal Police officer Stephen Daniel to get in touch with the New York office.

Within days, the response came: Detective Shank happened to be in Sydney. He could drive down to the capital that very week.

Holding Ms Benson's hand, the decorated officer admitted the request was one of the oddest he'd ever received in his 33 years on the force.

"I lost my father to Alzheimer's, so being here, [it's] a bit emotional but I've seen a lot and done a lot and this is one of the better moments in my career," Detective Shank said.

Ms Benson's younger brother John, who was quite enamoured with the detective's shining black shoes, said he couldn't believe it had all come together.

"After all this time, she's always wanted it, but she can't really travel any more ... it's marvellous."

Ms Sumner was also in tears as she watched the detective and his adventurous host take a stroll around the home.

"I always ask people 'what's something you've always wanted to do?'" she said.

"We've had someone go hot air ballooning and on a police ride-along with the siren, but this for me was the most emotional.

"Just the look on her face when she turned around and saw him behind her."

Detective Shank gifted Ms Benson with a special NYPD scarf "all the way from the streets of Manhattan" and made her promise to look him up if she did finally travel to New York.

"I'll show you round and take you out for a steak dinner," he said.

Ms Benson thanked the detective and instructed him to refer any "cross" senior officers her way if she'd made him late for important police work.

He could fill her in on the rest of his travels down under over a New York coffee.