'Ethiopian' : Shane Warne signs books for fans in 2006.

'Ethiopian' : Shane Warne signs books for fans in 2006. Photo: Vince Caligiuri

The autograph is dead, sport fans, long live the selfie.

Sports memorabilia has always been a luxury item, popular in boom times when the cash is flowing but one of the first things to go when times get tough.

Valuers of sport collectables say Test cricket's prized baggy green cap, their canary in the coal mine, is down 40 per cent in value since the global financial crisis and not showing signs of improvement.

'Beautiful hand': Peter Brock's signature on the dash of a limited edition HDT car.

'Beautiful hand': Peter Brock's signature on the dash of a limited edition HDT car. Photo: John French

But now there is something else for memorabilia companies to worry about, a declining interest in the celebrity signature.

Spin king Shane Warne predicted the demise of the autograph on Tuesday, telling Twitter that fans were increasingly likely to get a selfie than ask him to sign something.

"After doing 5 selfies with people this morning before 8am on my morning run / walk I've come to the conclusion that the autograph is dead !" he tweeted.

Sports memorabilia expert Rick Milne agreed the autograph was most definitely dead, but mainly because it's become more difficult to read the scrawl of the modern sport's star.

Mr Milne said today's sporting greats don't take as much pride in their signature as predecessors like cricket lothario Keith Miller or car racing champion Peter Brock, who had a "lovely hand".

"Because of the rise of the internet they don't practice penmanship anymore, they've completely lost the ability to write," he said.

"Warnie's ... frankly it looks like it's been written in Ethiopian."

Mr Milne said the interest in signed memorabilia had also been damaged by the mass release of "limited edition" collectibles by commercial operators such as Channel Nine.

However he said signatures of AFL greats like John Coleman or Jack Dyer were still highly sought after.

"If you've the good stuff it will always sell, especially if it has a bit of age to it," he said.

Michael Fahey, owner of Sports Memorabilia Australia, said the market for sports memorabilia is still soft after the global financial crisis, shown in something he calls the "baggy green index".

An expert in valuing Australian sport's most treasured item, Mr Fahey said the baggy green cap was a good indicator of demand across the whole industry.

"Limited edition framed memorabilia is very hard to sell. There's probably too much of it, some of it is quite unmemorable," he said.

Mr Fahey said some sports stars might like the death of the signature, if it means they can do away with overbearing autograph hunters trying to get hold of an elusive signature.

Big-name players have even been known to refuse a signature if they think someone is seeking to profit from it or to promote scarcity.

"It's been an ongoing tension with athletes and fans that people stalk them in hotels and airports and pretend to be a fan," he said.