Settlers' leaders have confirmed that construction has begun on around 600 new housing units in occupied West Bank territory since the Israeli settlement freeze ended.
The development was first revealed by the Israeli peace and justice group Peace Now, which campaigns for Palestinian self-determination within 1967 borders.
Foundations have already begun for at least 350 apartments, while construction of another 200 to 250 homes is in more preliminary stages, an official said over the weekend.
Another settler official said he believes some of the construction is actually more advanced, with 400 to 500 apartments having reached the stage of foundation work.
Yariv Oppenheimer, Peace Now's director, said last week that they had surveyed the construction activity and have since produced a detailed report.
"For more than seven years, the settlers in the outposts have enjoyed immunity and their breaking of the law in the territories has become a fact of life. The government is currently trying to rely on the political process in order to avoid enforcing the law in the territories," a spokesperson said.
The settlement construction issue is threatening to scupper on-off peace talks between Israel and the Palestinians, and there have been calls to end it from former US President Jimmy Carter, among other international observers.
Ghassan Khatib, a Palestinian government spokesperson, told CNN recently that the settlement building reports "are very alarming because it is happening on the expense of our basic rights, on our land, and because it will reflect negatively on the sincere effort that the United States and the Quartet members are undertaking to resume a meaningful political process."
Mr Carter, in Israel as part of a recent mission of senior figures called the Elders, told reporters he hopes Israel will cease its settlement activities and noted that Palestinian leaders said they would not go back to the table as long as the activity continues.
He also suggested that the United Nations could be asked for recognition of a state of Palestine on lands seized by Israel during the 1967 war: that is Gaza, the West Bank and East Jerusalem.