Sebastian Tibenham, the executive director at consultancy Pegasus Group, said elected mayor Steve Rotheram is likely to have to ponder the move even though the city region has healthy stocks of brownfield land.
The Liverpool city region combined authority, working with its six constituent local authorities plus West Lancashire Council, has started producing a spatial development strategy.
Tibenham, who heads the firm's Liverpool office, said: “Greenfield sites offer opportunities to deliver more affordable as well as market homes.
“Most in the market think they will have to do that. If green belt release is required and can be done in a sustainable manner, so be it.”
As an example of the challenges facing authorities that are keen to protect green belt, he pointed to the Merseyside authority of Wirral, which is part of the city region.
While the council has a policy aiming for a majority of its housing supply to cater for families, it also has an aspiration not to release green belt land and to focus on the vast Wirral Waters brownfield land project to regenerate the borough’s riverside.
Tibenham said: “The types of property attracted to that location are apartments that don’t sit with the need for more family housing.”
But he rejected any return to regional planning, arguing that it was “very difficult to believe” that the housing requirements of Greater Manchester and Liverpool city region cannot be met within their geographical areas, although he said the availability of land is “very tight” in Trafford.
“I would like to see where mayors get to before reinventing the wheel,” he added.
Planning for Housing 2020 North & Midlands was organised by Planning magazine, and sponsored by Kings Chambers and Pegasus Group.