Wellington - The New Zealand government, which has been reluctant so far to speak out on the conflict in the Middle East, issued a statement Wednesday saying it was "deeply worried by the mounting humanitarian crisis in Gaza as a result of the continuing Israeli ground offensive."

Foreign Minister Murray McCully said that attacks on United Nations facilities, including schools, in the Gaza Strip were of grave concern and underlined the need for both sides to agree to an immediate ceasefire.

"We call for Israel to immediately cease military attacks and for Hamas to immediately cease rocket and mortar attacks," he said. "Both sides have obligations to avoid putting civilians in danger.

"It is imperative both sides focus on the mounting humanitarian situation for the civilian population of Gaza."

The National Party-led centre-right government which was elected in November has been criticized for taking a softer line on the Israel-Palestine conflict than the former Labour administration.

The Labour leader, Phil Goff, said this week, "The size and scale of the Israeli response is hugely disproportionate and the timing appears to have been motivated more by the impending election in Israel than Hamas attacks."

But McCully told reporters earlier the government would not choose sides in the conflict. "We've avoided getting into a fairly pointless argument about who and what is a proportionate versus disproportionate response."

Some critics said the government was reluctant to criticize Israel because new Prime Minister John Key's mother was a Jewish Austrian who fled the Nazis.

A Catholic priest who splattered a mixture of his blood and red paint on a memorial to former Israeli prime minister Yitzhak Rabin in Wellington said Wednesday that it was a symbolic act and nothing compared to the killing taking place in Gaza.

Rejecting complaints about his action during a protest march against Israel's offensive in Gaza on Tuesday, Father Gerard Burns said, "I have a great esteem for the Jewish faith.

"I mean the founder of Christianity was Jewish, but the Israeli state is another beast altogether."

A group called Kiwi Friends of Israel said it strongly supported the right of all New Zealanders to have a robust debate on the rights and wrongs of Israel's policies but attacking peace memorials was not legitimate behaviour. (dpa)