An "intelligent and practical man", Mr Hopkirk could turn his hand at anything from computers to home renovation, Ms McIntosh said.
"He was the one his family and friends called on to help them and he never said no."
Mr Hopkirk grew up in Ardmore, Masterton and Lower Hutt, attending Naenae College and Victoria University in Wellington, where he completed a degree in botany.
"His beloved aunty recalls giving him a list of jobs on his frequent visits, which he would graciously work his way through. A real Kiwi guy, quiet and unassuming but strong and determined."
He had been deeply devoted to his late wife Pam and cared for her through a long illness, Ms McIntosh said. "He and his recent partner Belinda were inseparable; together they enjoyed a whirl of outdoor activities."
The couple had bought a bus and were planning to put their jobs on hold and go exploring.
"Having just returned from a trip mountain biking in National Park after Christmas, the early-morning balloon ride was a surprise gift from Belinda for Stephen's 50th birthday on January 7, something he had been wanting to experience.
"January 7 has always been a special day for the Hopkirk family. The day is Stephen's parents' wedding anniversary; they have been happily married for 56 years.
"Now, it will also be known for the day he died."
A spokeswoman for IBM, Elaine Koller, said Mr Hopkirk was highly regarded by colleagues and clients.
Ms Harter's son, James Harter, paid tribute to his mother, an "amazing woman", and Mr Hopkirk on Facebook.
"It's just impossible to ... comprehend she's gone, no more family games of 500 where she just can't resist giving hints and telling me off for not making every perfect card play, no more me telling her off for cheering wildly and embarrassing me at table tennis tournaments, no more her calling me 'Sweetpea' in front of my mates where they just can't help but giggle, no more hugs ... nothing," he wrote.
"Her and Stephen will forever be an inspiration to me and it's evident they've not only touched my heart but the hearts of many.
"I guess it's natural to sit back and wish they could have been around for longer but, hey life's not fair, and I suppose all that's left to do is cherish and be grateful for the times I spent with them."
additional reporting: Elizabeth Binning