Israel's education minister has said school textbooks should show Israel's pre-1967 borders, prompting a storm of criticism from right-wingers.
Ms Tamir (right) was a leading anti-settlement activist
Yuli Tamir said changes were needed to give Israeli children a proper understanding of their history.
Currently, schoolbooks show Israel's territorial conquests in the 1967 war - the West Bank, Gaza, East Jerusalem and the Golan Heights - as part of Israel.
International law deems them occupied land that Israel has illegally settled.
The dovish minister is reported to have ordered the books to be changed. There has been no immediate comment from the prime minister's office.
Ms Tamir's position is seen as a direct challenge to the Jewish settlement movement, which is a powerful interest group in Israel.
Settlers and their supporters have fought hard against any attempt by governments to withdraw from occupied land, either to foster peace with the Palestinians or enhance Israeli security.
About 430,000 settlers are thought to live in the occupied West Bank, including East Jerusalem, taken from Jordanian control in 1967.
Another 20,000 live in the Golan Heights which was captured from Syria, and annexed by Israel in 1981.
"You cannot teach history without knowing the borders Israel used to have," Ms Tamir told army radio. "We can't teach children what happened in 1967 if they are not aware where the border runs."
Right-wing MP Yitzhak Levy accused Ms Tamir of "politicising the education system".
Ms Tamir - who is a founder of the anti-settlement group Peace Now - countered criticism by saying that ignoring the facts of Israel's pre-1967 shape also reflected a political viewpoint.
Controversy over school textbooks is not a new phenomenon in the Middle East conflict.
Since the Oslo peace accords in the 1990s, successive Israeli governments have criticised the Palestinian Authority for textbooks which they said negated Israel's right to exist and incited anti-Israeli hatred among Palestinian children.