Foreign Secretary David Lammy has said the UK will be suspending 30 out of 350 arms export licences to Israel.
He said there was a "clear risk that they might be used to commit or facilitate a serious violation of international humanitarian law".
The items involved in the suspension of arms licences include parts for fighter jets, helicopters and drones.
Mr Lammy said this did not amount to an arms embargo, and the UK continued to support Israel's right to defend itself.
He said many had raised concerns about British arms export licensing to Israel over its military activity during the war in Gaza.
The foreign secretary said he immediately sought a review of British arms exports to Israel after the Labour government took office in July.
He said the review did not and “could not arbitrate on whether or not Israel has breached international humanitarian law”.
“This is a forward-looking evaluation, not a determination of innocence or guilt,” Mr Lammy said.
But he said the Strategic Export Licencing Criteria state “the government will not issue export licences if there is a clear risk that the items might be used to commit or facilities serious violations of international humanitarian law”.
Mr Lammy said: “It is with regret...the assessment I have received leaves me unable to conclude anything other that for certain UK arms exports to Israel, there does exist a clear risk they might be used to commit or facilitate a serious violation on international humanitarian law.”
He said the export licences suepended “include equipment that we assess is for use in the current conflict in Gaza”.