Arwin Adams, who has known Jelavich for 25 years, said the couple needed $12,000 for one round of IVF.
"She and her fiance have been denied public funding for IVF due to her age even though at the time of their application she was within the accepted range. This seems to be completely unfair to me.
"I wholeheartedly believe that she absolutely deserves the chance to be a mum and to deny this seems like the cruelest act."
Adams said she would have helped Jelavich herself with donor eggs or surrogacy but had had her own fertility issues, having concieved her own "miracle little girl" via IVF.
"This is the best way I can think to help.
"Even though my friend is the kind of person to generally have at least one job, sometimes two or three, she and her fiance just can't afford the $12,000 price tag.
"They will try to save this up but realistically her chances of success will probably drop considerably by the time that they can save that amount of money."
She said Jelavich would make an amazing mother.
"She has faced many challenges in life and yet is one of the happiest, toughest and most positive bubbly people I know.
"The love and support she has given her family over the years has been phenomenal and she currently helps young girls as a [Girl} Guide leader. She has so much boundless love to give.
"She would be one of the most amazing, loving, caring, super fun, generous and supportive mothers the world has even seen. The children she brings into the world would be such wonderful people and you can never have too many of them."
As well as age, to be eligible for publicly-funded treatment, women must be a non-smokers, a New Zealand resident, have a body mass index of under 32, and have experienced at least a year of infertility.
Success rates for fertility treatments decline with age and reduce quickly after 40.
If a woman is aged 30, a couple has a 47 per cent chance of a baby from one IVF cycle.
If the woman is aged 40, this drops to 23 per cent and less than 10 per cent for women aged over 42, Fertility NZ reported.
Although women aged over 40 can pay for IVF privately.
Infertility is defined as not conceiving after 12 months of trying.
The trend is rising - five years ago, one in six women experienced problems, support organisation Fertility NZ figures show.
In New Zealand, there are about 5000 first-time fertility clinic appointments every year.
In 1970, the median age a woman had her first child was 23, in 2016 it was 29, Statistics NZ reported.
