Metropolitan Sydney could see 36-metre-long B-triple trucks on the roads for the first time if a recommendation by a western Sydney council is accepted.

Blacktown City Council told the inquiry into a national freight and supply chain strategy it is willing to have the huge rigs serve its nine employment areas, which are situated near major motorways.

But the council said that it will cost $20 million to make local roads fit for the B-triple trucks.

The issue comes as the Blacktown local government area deals with pressing social and economic issues.

It is competing with Port Botany for a bigger slice of Sydney's growing container business, which is forecast to triple in the next 40 years.

The council is also positioning itself to take advantage of the job and business opportunities presented by the western Sydney Airport, due to begin operating by 2025.

At the same time it will have to house a significant percentage of the one million more residents forecast to be living west of Homebush in the next 15 years.

To meet the challenges, the council warns: "Major road and rail transport infrastructure needs to be fully funded and implemented within the next 15 years".

Its submission details priority road and rail projects, including the Outer Sydney Orbital Motorway, and recommends preserving the corridors needed for their construction.

Can B-triples be part of the solution?

Opinions vary on the safety of the trucks, which are about 36 metres long - 10 metres longer than the next smallest B-doubles.

Former New South Wales Roads Minister (and former truck driver) Duncan Gay described the rigs as "the safest trucks on the road".

Proponents such as the Australian Trucking Association say larger trucks also mean fewer trucks on the road.

But the NRMA has pointed out that B-triples weigh 74 times more than a family car, and that overtaking one is the equivalent of passing nine cars.

Spokesman Peter Khoury says the association needs to be convinced the rigs should be allowed on Sydney roads.

"We'd need to weigh up the productivity component with the safety component to make sure that it is something that we're able to do in Sydney without a massive impact on the road network," he said.

The New South Wales Government has been under pressure to increase the use of B-triples.

In 2012, the National Transport Commission said conditions in New South Wales were "stifling opportunities to improve national freight movement".

The general manager of Road Freight New South Wales, Simon O'Hara, said economic pressures made the use of B-triples east of the Newell Highway inevitable.

"We support Blacktown Council's submission, but only if the changes can be made harmoniously with the community."