One of downtown Vancouver's most recognizable landmarks could soon be getting a major makeover that would dramatically change the city's skyline.

A plan for the former Canada Post building on West Georgia Street has been proposed that would see three high-rise towers constructed on top of the sprawling steel structure, which has been a staple of downtown for more than 60 years.

The proposal, submitted by developer Bentall Kennedy, includes 427 rental apartments and 327 condos, with more than 25,000-square-metres of retail space and 47,000-square-metres of office space.

"Our vision, really, is to have a vibrant, mixed use, sustainable project here… a fun place to work, shop and be entertained,” company president Tony Astles said.

Astles said the project will also inject much-needed housing into a city that, despite recent indications of cooldown in the real estate market, remains embroiled in an affordability crisis.

"One of the key factors in making residential affordable in this city is increasing the number of units available to rent," he said. "We don't have enough now, so the prices are high."

The developer couldn’t say whether any of the units would be designated for affordable housing, however. Astles said it’s still early in the process, and the company has only just applied to have the property re-zoned.

Questions about the former Canada Post building's future have swirled since 2013, when it was sold by the federal government. Since then it's primarily been used for film shoots and for its parking space.

Judith Mosley, executive director of the Vancouver Heritage Foundation, said she's pleased that Bentall Kennedy’s proposal preserves the original structure, which she described as having great historical significance.

The Canada Post building was constructed in 1953 by prominent local architecture firm McCarter Nairne & Partners, Mosley said, and it was the largest welded steel structure in the world at the time.

"It was part of a period of great expansion and confidence in the post-war period in Vancouver," she said. "The sheer size of the building, its presence on West Georgia, and the expansion of the downtown area to that part of town are all part of what makes that building important."

The building isn't currently on the Vancouver Heritage Registry, but Mosley said there's always value in retaining older structures, particularly for a city focused on sustainability.

"There's a real connection between retaining and looking after our heritage buildings, reusing buildings and not just removing them and starting again," she said.

The City of Vancouver is in the process of reviewing the proposal, and if approved the developers hope to have the project completed by 2022.

Anyone who wants to provide feedback about the proposal can do so online at the city's website, or in person at an open house being held at the Fairmont Hotel Georgia on Nov. 22.

With a report from CTV Vancouver's Sarah MacDonald