"But you know, suddenly I was the oldest farmer in Southland," he said. "In fact, I'm probably the oldest farmer in New Zealand."
McKenzie has managers on his farms and he manages all the account information from his computer in his rest-home bedroom.
Every few months McKenzie's son and daughter come down from Christchurch to have meetings about the farms and take him out to visit them.
When McKenzie was 14, his father took him home from high school to work on the farm.
McKenzie said his father had two farms, his own and his mother's.
When his father bought his farm he paid £14 an acre for it.
"I worked at home, so I knew how to farm and then when I was 22, my father sold me what's now my home farm.
"When he sold it to me he had another son and daughter he had to provide for and I had to borrow money, so he took me down to the Bank of New Zealand in Wyndham and I borrowed £2000 at 5 per cent."
McKenzie said the bank manager asked him if he had any money and hesaid he had saved £400 from shearing and other jobs.
McKenzie got married in 1940 and said his wife had lived at home all her life, so when they set up they even had to buy teaspoons.
"We had nothing."
"So in fact when I went back to the bank, I only had £80 left, so I started farming with £80."
When he started, the farm was completely run down and he had to start from scratch, McKenzie said.
"I was big and strong and used my strength and got on top of everything."
"When I started farming I had 33 cows and 250 sheep. Now my sharemilker's got up to 700 cows.'
McKenzie said his father set up the Seaward Downs Young Farmers Club and he joined it when he was 28.
"I became the chairman and used to organise somebody to talk to young farmers at the monthly meeting, so they knew about things."
McKenzie said the group was told by one speaker that certain pastures were sour and the only action to take was to apply lime until it was neutral.
"The speaker said the trouble is people have been playing with it [lime]. You've got to put bulk quantities of lime on and he said you need to test your land, so I got him to test my land."
"The best paddocks needed three tonne of lime an acre and the worst paddocks needed five tonne of lime an acre."
McKenzie said he arranged to get 30 tonnes of lime delivered by rail to Edendale about every second day.
"Before I got the lime I was milking 50 cows and had a couple of hundred sheep."
"Within two years I was milking 80 cows and a couple of hundred sheep. The land just bloomed, it was incredible."