The Trades Union Congress has called on the government to end arms sales to Israel, but stopped short of potentially more significant measures at its annual conference.
The TUC's general council issued a statement on Wednesday condemning Israel's Operation Protective Edge in Gaza. General Secretary Frances O'Grady said the government's response to Israel's actions had been "unacceptable" and urged delegates to support the Palestine Solidarity Campaign.
Trade Union Friends of Israel (Tufi) director Steve Scott said there had been no significant change from the TUC's earlier position, but said it was outrageous that the statement had not highlighted Hamas rockets and other Gaza-based terrorist activity.
He said Israel supporters had feared delegates at the conference, held in Liverpool, would push for a split from the Israeli Histadrut union, or a possible expulsion from TUC for Tufi.
A spokesman for Fair Play, the Board of Deputies and Jewish Leadership Council's joint anti-boycott initiative, said the TUC's support of the PSC would mean it would now "provide the infrastructure of the anti-Israel boycott movement," he said.
Tufi held a fringe event on Tuesday attended by around 30 people.