Jessica McLennan, 23, died in hospital three days after a head-on car crash at Lilliput last month.

Friends and family members had gathered in the Royal Melbourne Hospital in such numbers as she fought to survive, they slept on floors and spilled out into the hallway.

Her fiance, Jarryd Hatton, later told the 1000 mourners at her funeral that “an angel grew her wings” when she passed away.

In her final act, Ms McLennan donated her organs to five people.

Her mother, Vicki Denniss, said the emergency and critical care nurse had always been a giving person.

“Nothing can describe how hard losing your child really is,” a still struggling Ms Denniss said.

“Nothing fixes it, but I feel like she goes on a little bit through others.

“There are other families there who won’t feel our pain.

“It was not our choice to donate, it was Jessica’s choice and we agreed to that.

“It meant so much to her – she was all about saving lives.”

Ms Denniss is urging people to sign up as organ donors.

Her recent Facebook post in support of donation has had nearly 6000 reactions and more than 1500 shares.

She hopes those with loved ones desperately needing a donation can avoid feeling the family's pain.

“I don’t want to see another mother or father watch their child pass away while waiting for a heart or lung transplant,” Ms Denniss said.

“I made the Facebook post and realised families could get some comfort from it.

“It might help other people sign up.

“I think organ donation crossed our minds before the crash but you don’t realise the urgency of it until you’re in that position.

“People think it’s a good idea but don’t get around to it.

“But it could have been their child.

“There could have even been the possibility that Jessica was in the car crash and needed organs to survive.”

Ms Denniss said Ms McLennan's father, Wayne, had been devastated by the loss but was proud of her organ donation. 

Speaking publicly for the first time since the incident, Jess’s older sister Kristy said the duo had been inseparable while growing up.

“I believe my life has prepared me for many things but the loss of my little sister was certainly not one of them,” she said.  

“She was the person I thought I'd have by my side forever. My heart breaks more and more each day that passes.

“She was honestly the most kindhearted, driven, honest, loving, successful and beautiful person I have ever known.

“I was lucky enough to call her my sister and spend 23 amazing years of my life with her.

“We were like chalk and cheese in our later years with some things yet identical with others.”

Kristy said she was struggling to come to terms with her death.

“There is an emptiness within my heart which can never be filled,” she said.  

“She is irreplaceable and I'd do anything to bring her back.

“Not just for me but for my daughter, Maddison – the love they shared was so pure and beautiful.

“She misses her Aunty Jess more than words could ever explain.

“Our family has been blessed to be surrounded by such a beautiful support network and I truly want to thank each and everyone of you, especially for not only caring about us but for loving my little sister so much.”

Ms Denniss hopes legislation can be softened so that organ donor recipients can have more contact with the families of recipients if both parties agree. 

“We feel that would help with the healing process,” she said.

Ms Denniss said limited contact could be made through letters, which sometimes had sensitive information censored.

DonateLife Victoria state medical director Rohit D’Costa said 253 people had donated organs in Victoria and NSW last year. 

Those organs had helped 763 recipients. 

“Part of the solution is people cementing their decisions by registering and having conversations with their families and friends about donation.”

Ms McLennan's family continue to support fundraisers set up in her memory including a Charles Sturt University and North East Health nursing scholarship, which can be donated to online.

Her mother said her friends and the wider community continued to help the family. 

While about 70 per cent of Australians say they would be keen to donate their organs, Dr D’Costa said only one in three adults were signed up. 

Only 1 per cent of deaths occur in situations where donations are possible, making the need for donors even greater. 

“It's quite remarkable how people's lives can be transformed or saved through the generosity of people they will never know,”he said. 

“It's also remarkable for me, as an intensive care doctor who works with patients who are dying and their families, to see how they have an ability to think about others at very difficult times in their lives. 

“At any time we have 1500 people on the national organ waiting list. 

“It's quite a rare and precious opportunity where donation is possible and when someone has made that decision to be an organ donor, it's something that's very much valued.”

Dr D’Costa said Victoria and NSW had the largest ever number of donors last year. 

"We know that Australians are incredibly generous, but we do need more donors,” he said.

The Rutherglen Netball Club has retired Ms McLennan's number 13 and her fiance has had “JM13” stitched into his football boots in her memory. 

Ms Denniss said Mr Hatton had been left “broken” by her death. 

“I don't think it's something you can ever get over,” she said. 

“People say as time goes by it gets easier, but it's probably gotten worse. 

“It has completely broken our family.

“We just try to do things in Jessica's memory. 

“We just want to do positive things in her memory.”

To register your donation decision online, visit  www.donatelife.gov.au.