A dispute has erupted over whether Pope Francis used the word "genocide" to describe the situation in Gaza during a meeting earlier with Palestinians.

Palestinian families whose relatives are being held in Israeli prisons met with the pontiff at his Vatican residence on Wednesday.

"When we shared the stories of the families that have been killed (in the besieged Gaza), he said, 'I see the genocide'," Shireen Hilal said at a press conference following the meeting.

She said the pontiff is well aware of what is happening in Gaza, including the lack of basic services and necessities such as water, electricity and medicine.

Following questions from reporters on whether the Pope used the word "genocide," Hilal noted: "It was very clear that the word 'genocide' did not come from us. It came from His Holiness, Pope Francis."

She said they invited the pontiff to Gaza, and he said this would be "a good idea" and that it could take place when conditions allow.

Meanwhile, in a written statement, Vatican spokesman Matteo Bruni did not confirm that Pope Francis used the word "genocide."

"I am not aware that he used such a word. He used terms that he expressed during the general audience and words that in any case represent the terrible situation that is being lived out in Gaza," he said.

Other Palestinian families who attended the meeting with the Pope also said they heard him use the word "genocide."

In response to a question on the same issue at a different event, Vatican Secretary of State Cardinal Pietro Parolin said "genocide" is a very technical term that applies to specific situations.

"I don't know if we can talk about genocide in this case," he said, the ANSA news agency reported.

Addressing his general audience, Pope Francis said he held separate meetings with Israeli and Palestinian delegations.