"Let me be clear: We will not participate in any arrangement that does not fully respect the humanitarian principles: humanity, impartiality, independence and neutrality," Guterres told reporters.
No aid has been delivered to the Palestinian enclave of some 2.1 million people since March 2. Israel has said it would not allow the entry of all goods and supplies into Gaza until Palestinian militants Hamas release all remaining hostages.
COGAT, the Israeli military agency that coordinates aid, last week met with UN agencies and international aid groups and said it proposed "a structured monitoring and aid entry mechanism" for Gaza.
"The mechanism is designed to support aid organisations, enhance oversight and accountability, and ensure that assistance reaches the civilian population in need, rather than being diverted and stolen by Hamas," COGAT posted on X on Sunday.
Jonathan Whittall, the senior UN aid official for Gaza and the West Bank, said last week that there was no evidence of aid being diverted.
Israel in March resumed its bombardment of Gaza after a two-month truce and sent troops back into the enclave.
"Gaza is a killing field – and civilians are in an endless death loop," said Guterres as he again called for the immediate and unconditional release of all hostages, a permanent ceasefire, and full humanitarian access in Gaza.
"With crossing points into Gaza shut and aid blockaded, security is in shambles and our capacity to deliver has been strangled," he said.
"As the occupying power, Israel has unequivocal obligations under international law – including international humanitarian law and international human rights law," Guterres said.
That means Israel should facilitate relief programs and ensure food, medical care, hygiene and public-health standards in Gaza, he said.
"None of that is happening today," he added.
Israel says it does not exercise effective control over Gaza and therefore is not an occupying power.
The war in Gaza was triggered on October 7, 2023, when Hamas killed 1200 people in southern Israel, and took some 250 hostages, according to Israeli tallies. Since then, more than 50,000 Palestinians have been killed, according to Gaza health authorities.
Meanwhile, as calls for Lebanon's Hezbollah to disarm gain momentum, a senior Hezbollah official told Reuters the group is ready to hold talks with the Lebanese president about its weapons if Israel withdraws from south Lebanon and stops its strikes.
US-backed President Joseph Aoun, who vowed when he took office in January to establish a state monopoly on the control of arms, intends to open talks with Hezbollah over its arsenal soon, three Lebanese political sources said.
Discussion of disarmament has intensified since the power balance was upended by the 2024 war with Israel and the ousting of Hezbollah's Syrian ally, former president Bashar al-Assad.
Hezbollah emerged severely weakened from that conflict with Israel when its top leaders and thousands of its fighters were killed and much of its rocket arsenal destroyed.
The senior Hezbollah official said the group was ready to discuss its arms in the context of a national defence strategy but this hinged on Israel pulling out its troops from five hilltops in south Lebanon.
Hezbollah's media office did not immediately respond to a request for comment. The presidency declined to comment.
