The number of will disputes reaching the Supreme Court has shot up by almost 60 per cent since 2005, with blended families, entitled grandchildren and burgeoning estate values driving up the number of claims.

While the death rate in NSW has increased by about 10 per cent over the past decade, fights over the family fortune rose by 59 per cent between 2005 and 2013.

Statistics from the Supreme Court of NSW show 919 will disputes were heard last year but legal experts say the real figure is much higher as about 95 per cent of claims are settled through mediation before they reach court.

Aitken Lawyers director Walter MacCallum said a growing number of will disputes involve grandchildren such as the recent Supreme Court case in which 46-year-old Robert Wilcox made a $1.1 million claim on his grandfather's $5.5 million rural estate, which had been left to his mother.

Despite not having worked in agriculture since 2001, the court found he was entitled to some money and ordered he be paid $107,000 to clear a tax debt.

Mr MacCallum said families can be torn apart by proceedings.

''If the matter is not resolved in mediation you more often than not basically have an irreparable family breakdown,'' he said.

''Having said that, the breakdown has often occurred before the claim has been made. Even with mediation, you don't see reconciliation between family members.''*

Wills and estates specialist Eric Butler said disputes can become very messy, especially when new spouses, former spouses and stepchildren are involved.

''Lawyers will always try to settle them at mediation,'' he said. ''The problem is the clients don't see they are stuck with the law. They can only feel their emotions and how unfair it is, and often it is really unfair.''

This does not deter people from making claims, with Mr Butler saying the increase is also fuelled by greater public awareness of legal rights under the Family Provision Act.

''There is a lot of negative comment about this area of law but the law has always existed,'' he said.

''I started advertising about 15 years ago to let people know they could challenge a will. It's not sinister. Like a lot of law, people didn't even know they had rights and now they do. There's always the argument that lawyers are out to get you but the reality is there are a lot of bad wills.''

A Law Society of NSW seminar on the Family Provision Act drew a record crowd, according to wills and estates spokesman Darryl Browne, who explained: ''Family provision does push people's buttons.''

He believes the increase in remarriage and second families has spurred on the growth in claims as well as the value of the potential spoils.

''There has been an enormous increase in the size of estates over the past 10 years,'' he said.

''It was rare to have an estate of more than $1 million 10 years ago, but now it's common due to the value of property and superannuation. People save unwittingly sometimes. There's more in the kitty, so there is more reason for people to pursue claims if they feel they have been slighted.''

* An earlier version included a reference to a Supreme Court case. This has been deleted.