Former teammates and international rivals have expressed sadness, shock and respect following the death of former Wallabies lock Dan Vickerman at age 37.

The Australian Rugby Union confirmed that Vickerman died at his family home in Sydney overnight.

It is understood there were no suspicious circumstances.

He leaves behind a wife and two young children.

Rest in Peace, Dan Vickerman. 63 Tests, three Rugby World Cups, infinite respect. https://t.co/9Vl33SrQGN pic.twitter.com/mTfur3GeTi

— Wallabies (@wallabies) February 19, 2017

Born in South Africa, Vickerman moved to Australia at age 21 and went on to play 67 Tests and three World Cup tournaments for his adopted nation from 2002-2011 before injuries forced his retirement in 2012..

He was renowned for his strong lineout work and aggressive approach on the ground.

“The rugby world is in shock today after news of the tragic passing of Dan Vickerman,” said ARU chief executive Bill Pulver.

“Dan was an uncompromising competitor who forged a wonderful international rugby career despite a number of injury setbacks along the way.

“He was an enforcer on the field and a much-loved character off the field.”

Post-retirement difficulties

Former Wallabies player and Brumbies captain Owen Finegan said Vickerman confided in his friends about the difficulties he faced after retiring from the game.

“We all play on an old boys team called the Silver Foxes and Dan had expressed a number of times how difficult his transition was and it is difficult for a lot of professional sports people, especially when you’ve had 10 or more years at the top of the game,” Finegan said.

Finegan said Vickerman’s wife and children will be offered help.

“I’m sure the whole rugby community will come around them. I’ve only heard for about — well it hasn’t even been 24 hours and you think to yourself could you have done anything to help him,” he said.

The Australian Rugby Union said sporting bodies needed to be vigilant in monitoring players transitioning into retirement. 

The ARU says sporting bodies need to monitor players transitioning into retirement. Photo: AAP

The ARU’s Rob Clarke said players and coaches had been offered counselling following Vickerman’s death.

“We as administrators need to continue to be ever vigilant,” he said.

“The transition from being a professional sportsman into the world after sport can be challenging, and we’ve seen it in a number of sports.”

The Wallabies, Wallaroos and Australian Sevens teams, the Australian Super Rugby franchises and the Rugby Union Players’ Association were quick to pay their respects to Vickerman, along with several of his former teammates.

There was a particularly poignant tweet from fellow lock Nathan Sharpe, who formed a formidable second row combination with Vickerman.

“I had my arm around you for most of our playing days brother. No words can express the sadness,” Sharpe tweeted.

I had my arm around you for most of our playing days brother. No words can express the sadness… https://t.co/xkxjG9UFoc

— Nathan Sharpe (@NathanSharpe5) February 19, 2017

‘He was a big man with a soft heart’

Vickerman’s last Test was the 2011 World Cup semi-final loss to New Zealand.

The All Blacks’ Twitter account was among the first of the international responses to the news.

The #AllBlacks join the rugby family in mourning the passing of former Wallabies lock Dan Vickerman. Rest in Peace. pic.twitter.com/uBxw8zK7tm

— All Blacks (@AllBlacks) February 19, 2017

Vickerman linked with the Brumbies on arrival in Australia and made his Super Rugby debut in the 2001 season.

Persistent problems with stress fractures in his right leg forced Vickerman to retire early. Photo: AAP

In June 2002 he made his Test debut in a 31-25 Wallabies victory over France.

After three seasons and 33 appearances for the Brumbies, he was signed by the Waratahs in 2004 and played five seasons and 53 matches for them.

After playing in his second Rugby World Cup in France in 2007, Vickerman withdrew from Australian rugby for three years to study in England.

He earned a degree in land economics from Cambridge University, where he played in two Varsity matches against Oxford, captaining the side to a 31-27 victory in 2009.

He returned to Australia in time to earn selection by Wallabies coach Robbie Deans for the 2011 World Cup.

Anyone in need of help can contact Lifeline on 13 11 14 or MensLine Australia on 1300 78 99 78.

-AAP