Craig Morrison has almost seen it all after a decade as a funeral director, and says step-children, multiple marriages and money are some of the common trigger points for divisions.

But his leading piece of advice to reduce the chances of tension at the sensitive time is for an individual to pre-arrange, whether paid or not, their own funeral.

"If you don't have anything in writing you can be in big trouble," he said.

It's advice Mr Morrison, the Canberra and Queanbeyan acting area manager for the InvoCare-owned trio of Tobin Brothers, White Lady and Simplicity funeral businesses, followed with his own now departed mother. They had the conversation which allowed her to set out what she wanted read at her funeral.

But even with more internet-savvy and better-researched generations leading the way, his mum is in a minority.

Not-for-profit The GroundSwell Project says 75 per cent of Australians have not had end of life discussions, and 45 per cent die without a will.

Mr Morrison's boss, Warwick Hansen, Invocare's regional manager, said only 15-17 per cent of funerals delivered by the three businesses nationally had been pre-arranged or pre-paid.

He said the percentages had changed little in 30 years and were consistent with those in Canberra, where the three businesses perform about 900 of the 2000-odd funerals each year.

"When there are divisions we need to deal with the executor, and if there's no executor, it gets very messy," he said.

Estates lawyer Barbara Campbell said similar principles applied when it came to wills, with fights between relatives, mainly centred around money, much more likely when a deceased had a blended family and no will.

The uncertainty created increased likelihood of claims challenging the default intestacy rules, including from partners raising oral agreements the deceased may have made, and divisions could be ongoing.

"In my experience, in many, many estate fights these families never get back to together, they implode and stay imploded, and the bitterness goes on for generations," she said.

Ms Campbell said the number of people dying intestate in Canberra was probably lower than the national average. She said a will had many important benefits even when money wasn't being fought over.

"One of the things we include in wills is digital memorandums – people can't access bank accounts and we had a mother of a 19-year-old who died and she couldn't initially get them off Facebook or the digital media, it's horrendous."

Ms Campbell said many people were unaware their marriage invalidated any earlier will. She also encouraged enduring power of attorney declarations to make it clear who would make difficult pre-death decisions when a loved one was incapable.

National Dying to Know Day, where families are encouraged to have discussions about death, is on August 8.

Leigh Nelson and her partner of 5.5 years Bill Spencer had no plans for death. Why would they? They were young, healthy, and had just bought their first house together in Dunlop.

But in October 2014, Bill, 26, suffered a catastrophic brain injury as a result of a fall from a skateboard while on the NSW south coast.

The lack of a will seemed a minor issue, but with the default intestacy rules providing Bill's parents with the large majority of his estate, the grieving partner could have lost out.

"Fortunately for me I'm very close to my partner's family," she said.

Bill's parents readily agreed for the estate to go to Leigh, allowing her to pay the mortgage and stay in the house the young couple had bought.

But she warns others there could have been a range of scenarios, including where a surviving partner and the deceased family did not get on, which would have threatened a very different outcome.

"I have raised it with a number of my friends, you've got to plan for the worst and hope for the best, if everything isn't sorted right you can end up in heartbreak," she said.

"I had to get written reports about the fact we were together, and all these stat decs from family and friends – it was still traumatic to describe your relationship when you didn't have it any more."

A fight over an estate could also bring financial pressure as funeral expenses and mortgage bills quickly gather.

"You don't want to worry about money, but finances are something that tear people apart," she said.

Solicitor Barbara Campbell said the risks became real for a mother whose son died after years of extra care and support from her.

The deceased's father, from whom his mother was divorced due to violence decades before, had done nothing for him. But without a will, a partner or any children, the son's estate by NSW law was left to his parents in equal shares.

"The adult son had wanted his younger brother to have special memorabilia and half of his estate along with his mother, a pensioner," she said.

"After litigation commenced the matter settled with the father receiving 30 per cent of the estate and the memorabilia despite owning two unencumbered properties of his own."