Israel's opposition Labour party has postponed its July primaries by one day to avoid clashing with a Tel Aviv concert by US singer Britney Spears, a senior lawmaker said Wednesday.

Former party leader and defence minister Amir Peretz said the Labour leadership fight had been scheduled for July 3 but had been pushed back to avoid clashing with the Britney show on the same date in Tel Aviv's Hayarkon Park.

Peretz, a likely contender to challenge Labour leader Isaac Herzog, said holding the election on the same day would present logistical problems, with gridlock expected on key Tel Aviv roads leading to the venue.

"We put it back one day to July 4," he told army radio. "They said there were likely to be traffic jams."