Oxfam's statement followed Johansson's announcement Wednesday that she was resigning her Oxfam role because of a "fundamental difference of opinion." Oxfam said it accepted her resignation.
The international humanitarian organization said Thursday that it believes SodaStream and other businesses operating in Israeli settlements in the West Bank contribute to the "denial of rights of the Palestinian communities that we work to support."
The charity says it opposes all trade from the Israeli settlements "which are illegal under international law."
Some 550,000 Israelis live in settlements in the West Bank and east Jerusalem, lands Israel captured in 1967, along with the Gaza Strip. The Palestinians seek all three territories for a future state.
Pro-Palestinian activists who advocate consumer boycotts of goods produced in Jewish settlements - which are deemed illegal by much of the international community - have encouraged the public to shun SodaStream. The company's main plant is in an Israeli industrial zone next to the settlement of Maaleh Adumim in the West Bank.
Johansson, who has become a global brand ambassador for SodaStream, is to appear in a high-profile SodaStream ad during the Super Bowl on Feb. 2.
The company makes home soda machines and home beverage carbonation systems. It hopes to use Super Bowl exposure to increase its U.S. market share, which lags far behind its market penetration in Europe.
Johansson's involvement prompted Oxfam to express concern about her role last week, setting in motion events that led to her resignation.
The company's chief executive, Dan Birnbaum, told The Associated Press 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 the SodaStream factory "for some political cause of some activists groups."
___ Ami Bentov in Tel Aviv contributed to this report.