Construction workers in New York have staged a major demonstration on Park Avenue to protest the developer of the city's vast Hudson Yards, because the company intends to use nonunion labour for the project's next stage.

A huge crowd of unionised workers took to the street for a planned protest on Wednesday, 22 August 2018. It targeted Related Companies, which is developing Hudson Yards – the huge development on Manhattan's West Side that includes buildings by Kohn Pedersen Fox, Foster + Partners, SOM and Diller Scofidio + Renfro.

Gary LaBarbera, president of the Building and Construction Trades Council, called for the protest after Related's plans to use open-trade or nonunion workers for the upcoming second phase were revealed.

The demonstration was described as a "personal attack" on Related's chairman Stephen Ross by Crains New York, which first reported the event.

The protest took place outside the 345 Park Ave office tower – the headquarters of the National Football League (NFL), where Ross has recently taken a spot on the NFL's social justice committee.

Demonstrators held signs reading "Steve Ross condones union-busting" and wore green jerseys that resemble the kit of the Miami Dolphins – the American football team owned by Ross.

These were emblazoned with "Step Down Steve", calling for Ross to leave his new position at the NFL. In total, 37 attendees are reported to have been arrested.

Latest in ongoing Hudson Yards dispute

The Park Avenue protest marks the latest in an ongoing feud between the Building and Construction Trades Council, and Related Companies, concerning the construction of Hudson Yards.

Earlier this year, Related Companies launched a $100 million (£77.8 million) lawsuit against union workers, accusing them of inflating costs of the project after finding a number of discrepancies and misconducts. As reported by the New York Post, these included workers logging extra billable hours, and the employment of a high-ranking union official for coffee runs – earning a high wage for a menial task.

The conflict also forms part of an ongoing debate in New York City around the use of union or nonunion labour. This year, Governor Andrew Cuomo promised that "there will never be a state project that isn't built with union labor" while he's governor.

Cost of union workers inflates New York's building projects

But many are critical that the cost of union workers is inflating building projects, particularly private schemes like Hudson Yards.

Some argue that rather than being anti-labour, Related's proposal to use nonunion workers is a method to help cut down on the fee of the project – estimated at a 20-25 per cent discount.

Related would also have to include some unionised labour, as Hudson Yards is so vast. The site is the largest private sector union construction worksite in New York City, explained an opinion article defending Ross.

The project spans a 28-acre (11.3-hectare) site on top of a rail depot, which will remain in use, and has required a huge infrastructure undertaking to achieve. Masterplanned by American firm Kohn Pederson Fox (KPF), it include sixteen new skyscrapers – making it the city's largest urban development since Rockefeller Center in the 1930s.

These include glass towers by KPF, Foster + Partners and SOM, some of which are already complete and others almost there.

A honeycomb of interlinked staircases by Thomas Heatherwick and an expandable cultural venue by Diller Scofidio + Renfro (DS+R) and Rockwell Group also form part of the new neighbourhood.