President Joe Biden's growing frustration with Israeli Prime Minister Benjamin Netanyahu continues to mount, with the Democrat captured on a hot mic as saying that he and the Israeli leader will need to have a “come to Jesus meeting”.

The comments by Biden came as he spoke with Senator Michael Bennet on the floor of the House chamber following Thursday night's State of the Union address.

In the exchange, Bennet congratulates Biden on his speech and urges the President to keep pressing Netanyahu on growing humanitarian concerns in Gaza. Secretary of state Antony Blinken and transportation secretary Pete Buttigieg were also part of the brief conversation.

Biden then responds using Netanyahu's nickname, saying, “I told him, Bibi, and don't repeat this, but you and I are going to have a come-to Jesus' meeting.”

An aide to the President standing nearby then speaks quietly into the President's ear, appearing to alert Biden that microphones remained on as he worked the room.

“I'm on a hot mic here,” Biden says after being alerted. “Good. That's good.”

The President on Friday acknowledged the comments, lightheartedly poking at reporters that they were “eavesdropping” on his conversation. Asked if he thought Netanyahu should be doing more to alleviate the humanitarian suffering, Biden responded, “Yes, he does.”

A widening humanitarian crisis across Gaza and tight Israeli control of aid trucks have left virtually the entire population desperately short of food, according to the United Nations. Officials have been warning for months that Israel's siege and offensive were pushing the Palestinian territory into famine.

Biden has become increasingly public about his frustration with the Netanyahu government's unwillingness to open more land crossings for critically needed aid to make its way into Gaza.

In his address on Thursday, he called on the Israelis to do more to alleviate the suffering even as they try to eliminate Hamas.

“To Israel, I say this humanitarian assistance cannot be a secondary consideration or a bargaining chip,” Biden said.

The President announced in his speech Thursday that the U.S. military would help establish a temporary pier aimed at boosting the amount of aid getting into the territory. Last week, the U.S. military began air-dropping aid into Gaza.

Biden said the temporary pier, ”will enable a massive increase in humanitarian assistance getting into Gaza”.

Later on Friday, Biden at a campaign stop in suburban Philadelphia told reporters that the prospects of forging an extended cease-fire agreement between Israel and Hamas before the start of Ramazan is “looking tough”. Ramazan is expected to begin on Sunday.

Biden also said that he was worried about violence spreading to east Jerusalem. Clashes have erupted during Ramadan in recent years between Palestinians and Israeli security forces around Jerusalem's Old City, home to major religious sites sacred to Jews, Christians and Muslims and the emotional epicentre of West Asian conflict.