Radio Dunedin announcer Neil Collins recorded the telephone interview with Sir Howard on Wednesday afternoon for his show.
It was aired yesterday morning.
Mr Collins and Sir Howard were long-time friends and hosted many shows together during his 50-year career.
The interview was as much a "catch-up" on an old friend, as it was a reflective chat about his career highlights, Mr Collins said.
While Sir Howard was his usual cheery self, he sounded breathless and chesty - occasionally coughing - during the interview from his home in Rotorua.
"Listening to the recording now, you can hear he doesn't sound well. I thought he may have just been tired from his trip," Mr Collins said.
The 74-year-old had recently returned from a holiday in Rarotonga where he was promoting Fight for the Future, a campaign aimed at improving Maori and Polynesian health.
He mentioned he had had a triple heart bypass in 1991 and that he had recently had a hip replacement, from which he had been slow to recover.
"I can't sprint down the street any more," he said with a chuckle, "but my pipes [voice] are still good."
Mr Collins, like many around the country, was shocked to hear of his passing.
"He was a great showman. I call him the Ed Hillary of entertainment in New Zealand."