Housing-finance giant Freddie Mac is expected to sell nearly $1 billion of commercial-mortgage bonds backed by multifamily loans Tuesday in an attempt to bolster the battered apartment sector, according to a person familiar with the deal.

This would be the first time that a commercial-mortgage bond is sold with the backing of a government-sponsored enterprise, or GSE. It also would be the first large commercial-mortgage bond deal in nearly a year.

This transaction is expected to open up a new way for Freddie to support lending in the multifamily market. Apartment and condominium complexes have been the most troubled in the real-estate sector.

Speculative developers built condominium towers and apartments at the peak of the housing bubble, especially in states like Florida, Arizona, Nevada and California. They are the worst-performing type of property among commercial mortgages.

Delinquency rates on loans secured by apartments and condos have risen, hitting 5.12% in April, said RBS research. The loss severity on this property type is more than 25%, as more than 754 loans have been liquidated.

Data released in the past week showed that new home construction in the U.S. fell to a fresh low in April, as a result of a drop in groundbreakings for high-rise towers and multifamily dwellings.

Freddie and its sibling Fannie Mae , which were taken over by the government last September, have held multifamily loans on their books without securitizing them. By packaging them into tradable bonds, Freddie will free up capital so that it can invest in more multifamily loans.

This comes at a time when Fannie has started securitizing home loans it holds in its portfolio. Fannie, however, hasn't sold them to investors yet.

Freddie has sold these multifamily loans that were held in its investment portfolio to a Deutsche Bank Trust, which will package and sell these bonds. The deal will be led by Deutsche Bank , according to the person familiar with the matter.

Market participants say this is a positive sign for the market and raises the prospect of more such deals from the GSEs.