Mr McDine, 46, announced today that he had resigned ahead of internal elections to be held early next year.
The union’s assistant secretary, Daniel Walton, will be acting national secretary and is expected to have the support of members to take over the position.
“The AWU means an enormous amount to me, so I took this action with a heavy heart,” Mr McDine said.
“However, nominations will soon open for our next union elections, so this is the appropriate time to announce I will not be recontesting my position.’’
Mr McDine rose through the union’s ranks after starting work at the Pinjarra alumina refinery in Western Australia in the 1990s.
After assuming the national secretary’s position in 2014, Mr McDine ditched the push by Mr Howes for a “grand compact” between business and unions. He hit out at the level of “navel-gazing” in the ALP and unveiled plans for a major campaign in favour of a gas-reservation policy nationally.
Mr McDine said yesterday the union’s ‘Reserve Our Gas’ campaign created a shift in the public debate about Australia’s natural gas.
“The pragmatic and constructive leadership of the AWU, combined with the courage of our members, was critical in saving the steel industry in Port Kembla last year, and guiding the Arrium administration process this year,’’ he said.
Mr McDine said he was looking forward to “taking a decent break”.
“I was involved in the AWU for almost 20 years before seeking a fulltime elected position,’’ he said.
“I never set out to achieve high office, so the last seven years have been an enormous privilege.
“And while I am stepping down from this role, I will always be a proud unionist. I will always believe in the importance of unions to working people.”