The statement, published overnight by the UK Foreign Office, describes conditions for civilians as "appalling" as winter approaches.
It said 1.3 million people urgently need shelter, and the majority of the population is experiencing acute food insecurity.
"More than half of health facilities are only partially functional and face shortages of essential medical equipment and supplies. The total collapse of sanitation infrastructure has left 740,000 people vulnerable to toxic flooding," it said.
"Whilst the amount of aid going into Gaza has increased since the ceasefire, the response remains severely constrained by persistent impediments on humanitarian access."
The statement was issued by the foreign ministers of Canada, Denmark, Finland, France, Iceland, Japan, Norway, Sweden, Switzerland and the United Kingdom.
It called on the government of Israel to allow more aid to enter, and to allow NGOs and the UN and its partners to keep working in Gaza.
A spokesperson from the Ministry of Foreign Affairs and Trade said the Prime Minister and Foreign Minister had already put New Zealand's views on the catastrophic humanitarian situation in Gaza on the record "on a number of occasions".
"We continue to call on the parties to exercise restraint, to fulfil their commitments, and to focus on the rapid and unimpeded delivery of humanitarian aid," they said.
The ministry did not say whether New Zealand had been invited to join.
