Israel was warned by Egypt of potential violence three days before Hamas' deadly cross-border raid, a US congressional panel chairman has said.

House of Representatives Foreign Affairs Committee head Michael McCaul told reporters of the alleged warning.

Israeli PM Benjamin Netanyahu described the reports as "absolutely false".

Israeli intelligence services are under scrutiny for their failure to prevent the deadliest attack by Palestinian militants in Israel's 75-year history.

"We know that Egypt has warned the Israelis three days prior that an event like this could happen," Mr McCaul told reporters following a closed-door intelligence briefing on Wednesday for lawmakers about the Middle East crisis, according to AFP news agency.

"I don't want to get too much into classified, but a warning was given," the Texas Republican added. "I think the question was at what level."