Reports of an impending Israeli attack on Rafah in southern Gaza have prompted the leaders of Australia, Canada and New Zealand into releasing a joint statement. They say the consequences would be "catastrophic."

Anthony Albanese, Justin Trudeau and Christopher Luxon say they are "gravely concerned."

They point out more than one million Palestinians are currently taking refuge in Gaza's southernmost city.

And they call for an "immediate ceasefire," including the release of Israelis being held hostage by Hamas.

Australian Foreign Minister Penny Wong described the possible assault on Rafah as "unjustifiable" and warned Israel not to "go down this path."

The three leaders issued another statement last December calling for an end to the "continuous suffering" inflicted on Palestinian people.