"The doctors have been able to stabilise Rick," the fellow Mid-Canterbury horseman said.
"They are not saying exactly what the problem is. They are calling it a medical event and saying it could have ben caused by a number of factors."
This morning, a hospital spokesperson told Radio New Zealand that he was now in a serious but stable condition in the intensive care unit
It is believed a young female driver, who was not participating in the race, was one of the first people to May's side following the incident and performed CPR on him.
May spent over an hour being stabilised by the local ambulance crews and has not being flown to Dunedin hospital yet.
He was diagnosed as being in a critical condition and it was deemed too dangerous to airlift him to hospital immediately but a helicopter taking him to Dunedin Hospital eventually lifted off at 6.15pm.
The crowd of about 5000 was left in shock by the incident. Many stood and cheered as the helicopter carrying May left the racecourse.
Afterwards, many people who went to cash in their tickets stayed to donate the money to St John's Ambulance or May's family.
Harness Racing New Zealand chairman Ken Spicer was at the race meeting.
"The quick actions of the horse people, racegoers and race-day staff may have saved Ricky's life,'' he said.
"It is important that everyone in the harness racing family gets behind Ricky and his family."
May was driving A G's White Socks for Canterbury trainers Greg and Nina Hope.
Greg Hope described May as a highly respected and popular driver.
"No-one has got a bad word to say about Ricky.
"He is a great friend of our family.
"Everybody in the industry is behind him and his family and all we can hope for is the best for him."
Hope said May appeared to be fit and healthy before the race.
"Before he got in the cart he was 100 per cent right — at no stage did he look crook."
May lives at a rural property near Methven with his wife, Judy. The couple have three children, Tim, Phil and Kate.
Racing Integrity Unit official Nigel McIntyre said May's colleagues unanimously agreed that the meeting should not continue.
"We met with all of the drivers and the Harness Racing New Zealand board members that were here and it was a unanimous decision that the meeting should not continue."
May is one of the most popular and successful harness racing drivers in New Zealand.
He has won 2948 races in New Zealand during a career of more than 40 years. That tally is the third-highest in the history of the sport in this country.
May has the greatest record of any driver in New Zealand's biggest harness race, the New Zealand Cup at Addington. He has won the race seven times.
