An Ottawa developer will be allowed to build a 20-storey tower and an adjacent 24-storey tower downtown as part of its bid to host the Portrait Gallery of Canada, Ottawa city council has decided.

The towers are twice as tall as what was previously allowed at Metcalfe and Lisgar streets, but Claridge Homes will be permitted to build the towers over a former parking lot there even if their design doesn't win the portrait gallery in the end, council ruled Wednesday.

In that case, however, the space would have to be used for a public facility such as a library, cultural centre or social services centre.

In November, the federal government announced that it wanted Halifax, Quebec City, Montreal, Ottawa-Gatineau, Toronto, Winnipeg, Edmonton, Calgary and Vancouver to bid for the gallery, which was originally slated for Ottawa.

In addition, Public Works Minister Michael Fortier said the government wanted to ensure maximum tax-dollar benefits by including the private sector.

The cities have until May 16 to submit their proposals.