Johansson has become the public face of the company which makes the famous appliance for injecting gas into still waters for domestic consumption.
She is due to appear in an advertisement for the company, which is expected to air during the American football Super Bowl final on Sunday.
However, her multi-million dollar deal with SodaStream has sparked a backlash among activists and humanitarian groups because the firm’s largest factory is based in a Jewish settlement in the occupied West Bank.
Some 550,000 Israelis live in settlements in the West Bank and east Jerusalem, lands Israel captured in the 1967 war, along with the Gaza Strip. The Palestinians seek all three territories for a future state.
SodaStream employs both Palestinian and Israeli workers and claims its plant offers a model of peaceful co-operation, but settlements have been ruled illegal under international law and have been condemned by Oxfam, which has a large operation in the Middle East.
After consultations with Johansson earlier in the week, the actress yesterday informed Oxfam that she would no longer work on its behalf.
“Oxfam has accepted Scarlett Johansson’s decision to step down,” the charity said in a statement. “Ms Johansson’s role promoting the SodaStream company is incompatible with her role as an Oxfam global ambassador.
“Oxfam believes that businesses, such as SodaStream, that operate in settlements further the ongoing poverty and denial of rights of the Palestinian communities that we work to support.”
The controversy has come at a delicate time for US-backed peace talks between Israel and the Palestinians. Israeli officials fear that if the talks fail, a nascent call for an economic boycott of Israel and its settlements might gather momentum.
Israel has already withdrawn from Gaza but continues to blockade it.
In a statement, Johansson’s spokesman said “she and Oxfam have a fundamental difference of opinion in regards to the boycott, divestment and sanctions movement”.
The statement added: “SodaStream is not only committed to the environment but to building a bridge to peace between Israel and Palestine, supporting neighbours working alongside each other, receiving equal pay, equal benefits and equal rights.”
The boycott Israel movement, sponsored mostly by pro-Palestinian intellectuals and bloggers, advocates a blanket boycott of all Israeli goods and questions the legitimacy of Israel’s policies.
International rights groups such as Oxfam, however, limit their criticism of Israel to its illegal occupation of West Bank territory. “The very existence of [Israeli settlements] amounts to a serious violation of international law,” the New York-based Human Rights Watch said.
“It is impossible to ignore the Israeli system of unlawful discrimination, land confiscation, natural resource theft, and forced displacement of Palestinians in the occupied West Bank, where SodaStream is located,” the rights group added.
The company’s chief executive, Dan Birnbaum, yesterday said that the campaign to boycott products from Israeli settlements had not had any impact on SodaStream.
“To the best of my knowledge, we have not lost a single customer,” he said. “If anything, it advances our awareness around the world, because people are talking about SodaStream.”
He said the company does not want to “sacrifice” the jobs of 500 Palestinians who work in its West Bank factory “for some political cause of some activists groups”.
Johansson became an Oxfam ambassador in 2007.