"We reiterate our opposition to a full-scale military operation in Rafah that would have catastrophic consequences on the civilian population," read the appeal, sent by the countries' foreign ministers to their Israeli counterpart Israel Katz and made public.
The signatories were Australia, Britain, Canada, Japan, New Zealand, South Korea and EU member states Denmark, Finland, France, Germany, Italy, the Netherlands and Sweden.
The ministers welcomed recent measures adopted by Prime Minister Benjamin Netanyahu's cabinet to improve the flow of international aid into Gaza, but called for "further steps".
"We urge the Government of Israel to let the humanitarian aid enter into the Gaza strip through all relevant crossing points, including the one in Rafah," they said.
They called on Israel to take "concrete action for the protection of civilians, international and local humanitarian aid workers and journalists".
The appeal also called for "a sustainable ceasefire".
The ministers urged Israel to "open all possible overland supply routes into Gaza" for aid, to "resume electricity, water and telecommunication services", and boost significantly "the supply of critically needed goods... particularly medical supplies".
Finally, they called on Israel to "facilitate further evacuations by issuing exit permits for all our citizens, eligible persons, and Palestinians admitted to relocate for humanitarian or medical reasons abroad".
Eight months after the start of the war, Israel is vowing to intensify its ground offensive in Rafah despite international concerns for the hundreds of thousands of displaced Palestinians in the southern city.
The Israeli siege of Gaza has brought dire shortages of food as well as safe water, medicines and fuel for its 2.4 million people.
The arrival of occasional aid convoys has slowed to a trickle since Israeli forces took control last week of the Gaza side of the Rafah crossing.
The war broke out after the October 7 attack on southern Israel which resulted in the deaths of more than 1,170 people, mostly civilians, according to an AFP tally of Israeli official figures.
Out of 252 people taken hostage that day, 128 are still being held inside Gaza, including 38 who the army says are dead.
Israel vowed in response to crush Hamas and launched a military offensive on Gaza, where at least 35,303 people have been killed since the war erupted, according to data provided by the health ministry of Hamas-run territory.