The £53m Riverside scheme, 17 storeys high, was meant to complete this year before Carillion went into liquidation in January.
The £100m Riverview development, 35-storeys high, was scheduled to open by the end of 2019.
Between then, the two developments comprise 505 apartments. They will now be compeleted by Sir Robert McAlpine.
Mark Oakes, chief commercial officer of Select Property Group, said: “Thanks to the proactive approach of our team we have been able to expedite what can ordinarily be a lengthy process. We are delighted to have the Sir Robert McAlpine team on board to complete the scheme and we look forward to updating the industry in the coming months.”
Sir Robert McAlpine regional managing director Simon Trevor said: “The Riverside and Riverview schemes are significant projects in Manchester and it’s a pleasure to be starting work with the Select Property Group team.”