Unions will refuse to work on any redevelopment of the historic Curtin Hotel in Melbourne, in a 1970s-style "green ban".
The Curtin Hotel, which sits across the street from the Victorian Trades Hall Council building, is known for its links to the state's union movement and the Labor Party.
Bob Hawke famously used a hotel as a second office while he was ACTU president and later prime minister.
The managers of the hotel revealed in February that the building was set to be sold at the end of the current lease and it is understood the iconic pub has now been sold.
The CBRE commercial real estate agency was handling the sale, but has not revealed information on the buyers or their plans for the site.
Victorian Trades Hall Council Secretary Luke Hilikari said union members won't work on any project at the site that doesn't respect the hotel's history and significance.
"We are really worried that an international developer is going to come in and create apartments in a really historically important building for Melbourne," he said.
Unions 'up for the fight' over hotel
Mr Hilikari said a return to green bans, which affected millions of dollars worth of projects in the 1970s, was not a move unions took lightly.
"Green bans have made sure that we've preserved the heart of what is Melbourne. It's sad that we have to do this again but we have no other choice," he said."
"We're up for the fight, so if someone wants to rip this place down and turn it into apartments they can expect pretty rough going in Victoria."
Green ban a throwback to the 1970s
Green bans were a distinctly Sydney thing in the early 1970s, but Melbourne also had its fair share.
The term "green ban" was coined by the Builders Labourers' Federation to describe a refusal to work on projects on environmental or social responsibility grounds.
Unions already had "black bans" against projects or employers that didn't pay their workers well, or wronged the unions in some other way.
The first green ban was enforced in 1971 as developers moved in on a section of parkland in Sydney's Lower North Shore called Kelly's Bush.
Residents started a campaign that drew the support of the BLF and eventually saved Kelly's Bush, which exists to this day.
Green bans on dozens of other projects in Sydney followed throughout the early 1970s.
In Melbourne, green bans were not as regular, but still highly effective ways of preserving green space or historically significant buildings.
In the early 1970s, when Flinders Street Station was very much out of favour with Melburnians, plans were drawn up for a radical redevelopment of the site.
The redevelopment could have seen much of the station demolished, and replaced by two large office towers in a move that seems almost ludicrous by today's heritage standards.
Unions enforced a green ban at the site, and much of the station was eventually retained.
