A Canadian high-rise developer may construct up to 2 million square feet of residential space across the street from Amazon.com’s world headquarters, taking advantage of new height limits in the South Lake Union area.

In documents filed recently with the city, Vancouver-based Onni Group describes plans to build four residential towers on two full city blocks it is buying from The Seattle Times.

City rules allow building heights up to 240 feet on one block and up to 400 feet on the other block, at Fairview and Denny. In residential towers, each floor is typically about 10 feet high.

In July, Onni bought the block at Fairview Avenue North and Denny Way for $33.5 million. It is expected to close this month on the adjacent block north of John Street for $29 million.

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An Onni executive didn’t respond to requests for comment.

Preliminary site plans call for about two-thirds of each block being developed, with walkways mid-block leading to central, publicly accessible courtyards.

On each block, two residential towers would rise above a “podium” between 45 feet and 65 feet in height. It’s unclear whether the podium will be primarily for retail or other uses. The documents also indicate there will be below-grade parking.

John Street would be lined on both sides with retail shops totaling about 18,000 square feet,

the documents indicate.

While the site plans don’t say how tall the towers might be, a preliminary application filed with the city says the project “will take advantage of height bonuses through affordable housing,” among other things.

In an interview this summer, Onni Group’s Executive Vice President Chris Evans said the project was his company’s entry into the Seattle market.

Most of Onni’s other residential projects are high-rise towers in major cities.

The preliminary documents don’t give any indication of Onni’s timeline.

Other developers said the mega-project would almost surely be carried out in at least two, if not more, phases.

Via6, a 654-unit development opened last spring on a half block in the Denny Triangle, was one of the largest to open in Seattle in a single phase, said Matt Griffin, managing partner of developer Pine Street Group. It consists of two 24-story towers on a podium, Griffin said.

Sanjay Bhatt: 206-464-3103 or sbhatt@seattletimes.com On Twitter @sbhatt