The UK government must ensure that military equipment sold to Israel is not used in the occupied territories, MPs have said.
Ministers must learn "broader lessons" about ensuring the ban on the trade in such products for use in Gaza and the West Bank is enforced, a report adds.
The MPs said it was "regrettable" that UK arms sold to Israel were "almost certainly" used in Gaza in 2008.
However, they said the UK provided less than 1% of arms exported to Israel.
Rocket attacks
The Commons Committees on Arms Export Controls - made up of members of other select committees - questioned ministers on the state of the military equipment trade.
It heard that arms deals with Israel had been looked at on a "case-by-case basis", rather than the UK government imposing an embargo.
Five licences had been revoked since Operation Cast Lead, launched by Israel in December 2008.
The Israeli armed forces launched a 22-day offensive against the Gaza Strip, bombing Palestinian cities before sending in ground troops - in response, Israel said, to Hamas rocket attacks on southern Israel.
After this, Hamas launched its rockets in increased numbers at Israeli towns near the Gaza Strip, before agreeing to a ceasefire.
Palestinians and rights groups say more than 1,400 Gazans died in the conflict but Israel puts the figure at 1,166. Thirteen Israelis, including three civilians, were killed.
A report issued in September 2009 by the UN Human Rights Commission found that Israel and Hamas, the militant group that runs Gaza, had committed war crimes during the conflict.
In their report, the MPs said: "We repeat our conclusion that it is regrettable that arms exports to Israel were almost certainly used in Operation Cast Lead.
"This is in direct contravention to the UK government's policy that UK arms exports to Israel should not be used in the occupied territories.
"We further conclude that the revoking of five UK arms exports licences to Israel since Cast Lead is welcome, but that broader lessons must be learned from the post-conflict review to ensure that UK arms exports to Israel are not used in the occupied territories in future.
"We recommend that the government, in its response to this report, set out clearly the longer term lessons learnt post-Operation Cast Lead and how they will impact in practice on the issuing of future licences for arms exports to Israel."
'Take Gaza into account'
In evidence to the MPs in April last year, Bill Rammell, then a Foreign Office minister, said the government had not authorised any exports relating to F-16 jets, helicopters or armoured personnel carriers for Israel since the conflict in Lebanon in 2006.
He also said that "all of these export decisions were in accordance with the criteria on that information that we had available at the time".
But Foreign Secretary David Miliband made a statement on 21 April last year, in which he said the F-16s and Apache helicopters used by Israeli forces during Operation Cast Lead had "almost certainly" contained British-supplied components.
In their report, the MPs said: "The government stated it would take the conflict in Gaza into account in assessing all future licence applications."
They added: "The government wrote to the committees in July 2009 with an update on the review of 182 extant licences to Israel.
"It decided to revoke five licences for equipment to the Israeli Navy. It stated that there was no evidence that the decision to revoke those licences has had any impact on the UK's defence relationship with either the USA or Israel."
The Campaign Against the Arms Trade, which also gave evidence to the MPs, said it was "virtually impossible to guarantee that any military equipment supplied to the Israeli government will not be used in the occupied territories".
It called for an embargo on arms and components going to Israel, both directly and through use in weapons produced in other countries and then sold on to Israel.
The campaign said the government had licensed arms exports worth between £10m and £30m a year for export directly to Israel over the past few years.
During 2008, licences for goods worth more than £27.5m had been approved, it added, while the UK had sold components used in weapons exported to Israel by US suppliers.
In evidence in January this year, Foreign Office Minister Ivan Lewis said there would "not be any arms embargo against Israel" as the government was "firmly of the view that Israel faces real threats".
Israeli tanks advanced briefly into the Gaza Strip at the weekend, following clashes in which two Israeli soldiers and two Palestinian militants died.
It is the first time Israeli soldiers have died in Gaza since Operation Cast Lead.
