Israel's navy patrols Gaza's coast and shelled it during Operation Cast Lead
The UK has revoked five export licences for equipment to the Israeli navy because of actions during Israel's Operation Cast Lead in Gaza this year.
The British Foreign office said the exports would now contravene its criteria for arms sales, but denied that it had imposed a partial embargo.
The UK says it does not sell weapons which might be used for internal repression or external aggression.
Israel says its troops complied fully with international law during missions.
The 22-day operation which ended on 18 January has been widely condemned as disproportionate by critics.
The British government has been challenged by human rights groups and members of the UK parliament over concerns raised by Amnesty International that British-made equipment was used illegally in Gaza.
Amnesty says both Israel and Hamas committed war crimes during the conflict.
In April, the British government issued a statement saying it had not contravened its own guidelines, which it described as "stringent", but said it was was reviewing existing licences.
On Monday, the Foreign Office said in a statement that it had conducted the review, and found "in a small number of cases Israeli action in Cast Lead would result in the export of those goods now contravening the
An unnamed Israeli official said five of 35 contracts for naval equipment had been cancelled.
Media reports quoted Israeli officials as saying these all related to the Saar 4.5 gunboat.
In April, the British Foreign Office said there were "credible reports" that the vessels had been used in a "naval fire support role" during Operation Cast Lead.
DIFFERENT DEATH TOLLS
Palestinians killed during Israeli military offensive in Gaza, 27 Dec to 18 Jan - Palestinian claims followed by Israelis claims:
Total dead: 1,434 / 1,166
Non-combatants: 906 / 295-460
Children under 16: 288 / 89
Sources: Palestinian Centre for Human Rights and Israeli Defence Intelligence Research Dept
The British Foreign Office said future decisions would "take into account what has happened in the recent conflict".
"We do not grant export licences where there is a clear risk that arms will be used for external aggression or internal repression," it said.
Israeli Foreign Minister Avigdor Lieberman told Israeli public radio: "We've had many embargoes in the past... We can manage. This shouldn't bother us."
Palestinian rights groups say about 1,400 Palestinians died during the operation.
Thirteen Israelis died during the conflict, 10 of them were soldiers serving in Gaza.
Israel said its operation aimed to reduce rocket fire from Gaza aimed at its southern towns.