Noting that the tracing of family trees is becoming increasingly popular, vice president of the Society of Australian Genealogists Martyn Killion explained the role a will can play.
He explained that searching for ancestors can often be a difficult task, but such documents are "an incredibly rich source of information".
Mr Killion was speaking ahead of Good Will Week, which begins in New South Wales, Australia this weekend and is aimed at encouraging people to make wills.
One of the campaign's organisers, Peter Whitehead, said: "We strongly recommend all parents have a will and make sure this is up-to-date to look after children in their family."
The National Consumer Council recently found that 27.5 million people in the UK are yet to make a will, while three in ten people have never even thought about doing so.
