Israel's Civil Administration has declared 800 hectares in the occupied West Bank to be Israeli state land, the Israeli broadcaster Kan reported on Friday.
The report said hundreds of settler homes are to be built on the land, located near an existing Israeli settlement in the north-east of the West Bank, close to the Jordanian border.
Israeli settlements in the West Bank are illegal under international law.
The Israeli human rights organization Peace Now said this is the largest land seizure since the Oslo peace treaty signed by Israelis and Palestinians in 1993.
"The year 2024 marks a peak in the extent of declarations of state land," the organization said in a statement.
Peace Now accused Israeli Prime Minister Benjamin Netanyahu and Finance Minister Bezalel Smotrich of acting "for the benefit of a handful of settlers" against the whole world and the interests of the people of Israel.
Smotrich, a far-right politician, is responsible for part of the Civil Administration, the Israeli government authority in the West Bank. He also favours annexing the West Bank.
Peace Now also sees the move as a provocation against the US government, which recently imposed sanctions and entry restrictions on Israeli settlers in the West Bank.
Washington sees new settlements as counterproductive to lasting peace. US Secretary of State Antony Blinken visited Israel on Friday and met Netanyahu and others.