Former All Blacks star slams veteran commentator Keith Quinn's 'harmful' Twitter post

Former All Blacks star Zac Guildford has hit out at veteran rugby commentator Keith Quinn's advice to New Zealand men to "harden up".

Quinn sparked controversy on Twitter on Monday night with the post in which he questioned "bloke- ism".

"What's happening to bloke-ism? In the TV news the last few days Dustin Johnson, Lewis Hamilton & Puma rugby players & coach all crying their eyes out. Would the sight of All Blacks wearing pink boots have moved Pinetree Meads? I doubt it. Harden up - blokes of today," the broadcaster posted.

After a meteoric ascent into representative rugby, including being part of the victorious All Blacks squad at the 2011 Rugby World Cup, Guildford has been plagued by off-field problems with alcohol and depressions, including a much publicised 2011 incident at a Rarotonga resort where he assaulted a patron while inebriated.

Guildford also sensationally walked out on French club Nevers early last year - only months after signing a new contract.

In an interview with NZME on Tuesday, Guildford described Quinn's comments as "outdated" and "damaging".

"Having not been able to open up and keeping it bottled up, my emotions eventually boiled over and got the better of me," Guildford said.

"One comment by someone like that, in a position of authority can undo a lot of good work that others are putting in, moving rugby forward.

"It was a huge factor in jeopardising my career because all my feelings I had inside had no way to come out, except when I was drinking and when they came out, they came out in a bad way."

While not directly replying to Quinn's tweet, All Blacks icon Sir John Kirwan also made his stance clear, posting, "My highlight from the weekend was the team and Mario Ledesma crying, made me cry. Beautiful," he wrote.

Dozens of other Kiwi Twitter users replied to Quinn's tweet expressing their disappointment at his views.

"No Keith you've got this exactly backwards," one Twitter user replied. "It's great to see top sportsmen unafraid to express emotion, and explicitly rejecting the 'harden up' ethos of years gone by. More of this please."

"This makes me really sad. I grew up watching rugby with my dad by my side and you in our ears. Dad's gone now but he was learning to mellow as he aged and be less repressed about his feelings. I hope you can learn that too," another Kiwi said.

Quinn eventually backtracked from the initial comment, posting: "Point taken everyone. For the record and in all seriousness I think it's great these days that men can openly express their emotions. I often do myself. I was really just thinking of the differences from earlier times."