The organization, which monitors settlement activity, reported the new construction Saturday and said approval had been granted at the end of April.
The homes would be built in the Beitar Illit settlement.
The Peace Now report said plans for construction of a home for the elderly and a commercial project in the settlement of Efrat also were approved.
"The approval for marketing is the last approval required from the government before the construction in the settlements can start. Following this approval, the Ministry of Housing will publish tenders offering the project for bidding. The winning contractors will be able to start the construction as soon as they get a construction permit from the local municipality, which is a bureaucratic procedure that doesn't require another approval by the government," the report said.
Peace Now criticized the ministry's action, calling it especially harmful as it expands the size of land that Israel will need to swap with the Palestinians as part of a two-state agreement.
"This construction might create facts on the ground that will make the price of peace much higher for Israel," the report asserted.
The organization maintained that since the end of a 10-month settlement moratorium in September 2010 construction of some 2,000 housing units in 75 settlements has begun.