Maritime Union of Australia National Secretary Paddy Crumlin has congratulated Scott McDine on his ascension to the role of National Secretary of the Australian Workers' Union.
Mr McDine succeeds Paul Howes, who had occupied the position since 2007.
Mr Crumlin said the AWU and the MUA had shared a cooperative and effective partnership in modern times and he was confident that would grow under Mr McDine's leadership.
"Scott and I have been mates for years and I know him to be a man of integrity and intelligence. I have no doubt he will be an excellent leader of the AWU and on behalf of the MUA I wish him very well," Mr Crumlin said.
"Scott has risen to the top of his union from the grassroots, starting out as serviceperson at the Pinjarra alumina refinery in WA in the 1990s. That's a path we in the MUA understand and respect.
"The MUA and the AWU shared closer ties than ever under the leadership of Paul Howes and I am confident we can build on that relationship, of behalf of workers, with Scott."
Mr Crumlin said the MUA was determined to work in effective alliances with other unions where circumstances required.
"The MUA and AWU both want to fight against unsafe work practices in the offshore oil and gas industry. Our Offshore Alliance has played an important role in delivering a safe workplace in an industry where safety must play a vital role," he said.
"More than ever we need unions to be recognising where the real threat comes from. We have a federal government with an ideological bent against unions and bosses who are emboldened by their approach.
"Workers need their unions to be working effectively together in the interests of the country. I look forward to doing that with Scott in the months and years ahead."