France's foreign minister will travel to Cairo on Wednesday in an unscheduled stop during a Middle East tour as efforts to secure a truce between Israel and Hamas in Gaza reach a critical point, a French diplomatic source said.

Diplomatic efforts towards securing a ceasefire were intensifying following a renewed push led by Egypt to revive stalled negotiations between Israel and Hamas, Gaza's ruling Palestinian group.

"The surprise visit of the minister is in the context of Egypt's efforts to free hostages and achieve a truce in Gaza," the source said.

France has three nationals still held hostage by Hamas after the group's assault on Israel in October.

Foreign minister Stephane Sejourne's trip to Egypt follows stopovers in Lebanon, Saudi Arabia and Israel. He will likely want to assess whether those three hostages could be released and how close a deal actually is.

Sejourne, who saw Israeli Prime Minister Benjamin Netanyahu in Jerusalem on Tuesday, said in an interview on Tuesday that there was some momentum towards an accord, but that it would only be a first step towards a long-term ceasefire.

He warned that an offensive in southern Gaza City of Rafah would do nothing to help Israel in its war with Hamas.