Mr Griffiths added that he believes the UN is “very cautious with these figures and I think it’s not right to blame the messenger who is trying to get the truth out of what is a very complicated situation”.
The reduced totals of dead women and children cited by the UN provoked a storm of criticism within Israel.
The foreign ministry said: “Interestingly, the [UN] did not release any press releases or statements, almost as if this reduction was a secret.
“They recently had trouble explaining why there was such a disparity in the numbers in the first place.”
Israel Katz, the country’s foreign minister, called on António Guterres, the UN secretary general, to step down.
On Tuesday, Christian Lindmeier, a spokesman for the WHO, insisted that casualty figures from Hamas could still be relied on, despite the discrepancy revealed by the UN.
He said: “Nothing wrong with the data, the overall data [more than 35,000] are still the same. The fact we now have 25,000 identified people is a step forward.”
Death toll expected to rise
The UN has said it expects the death toll of women and children to rise as more identifying information is found.
Death figures provided by the Gaza Ministry of Health have proved accurate in previous rounds of fighting. However, they do not distinguish between civilians and Hamas members.
Meirav Eilon Shahar, ambassador and permanent representative of Israel to the UN and international organisations in Geneva, said on Twitter: “Seriously WHO? There is ‘nothing wrong with the data’ provided by the Hamas-run Health Ministry?
“What about the issue: Hamas does not differentiate between civilians and terrorists! Let alone relying on the figures of a terrorist organisation.
“For months, the WHO and the UN have continuously shared unverified information – one might say misinformation.”
Despite the UN changing its estimate in the latest report, the Palestinian Red Crescent issued a statement on Thursday claiming over 15,000 children had been killed in Gaza.