The 61-year-old, who had surgery on a brain tumour last year, became sick again last week.
Longtime friend and horse racing broadcaster Des Coppins said it was a tough time for everyone, particularly for Leishman's wife Michelle and the couple's three children Harry, India and Lily.
Coppins said last night they were trying to make things as comfortable as they could for Leishman and the family were taking things one step at a time.
"We know the inevitable's there - everybody knows he's got serious cancer," he said. "They're receiving support left, right and centre. They're a very close-knit family. He's in the public eye, but they're a very private family."
Coppins had talked to his old mate a few days ago.
Coppins, who was best man at the Leishmans' wedding, said he had received dozens of messages from people around the country.
"We work [together] and we were and we are close mates. We'll be there forever. He's almost a brother - in fact he's a brother - that's the way I see Phillip."
- Vaimoana Tapaleao of the NZ Herald
