In a scathing critique of Israeli actions leading up to the conflict, the UN's chief humanitarian co-ordinator in Israel, the former Australian diplomat Maxwell Gaylard, also accused Israel of failing to honour its commitments to open its border with Gaza during several months of truce from June 19 last year.

"The Israelis would not let us facilitate a regular and sufficient flow of supplies into the strip," Mr Gaylard said.

The chief spokesman for Israel's Ministry of Foreign Affairs, Yigal Palmor, said the criticisms of Israel policy amounted to "unqualified bullshit".

"At no time was there a shortage of food in Gaza over the last three weeks," Mr Palmor said.

Mr Gaylard, who is the UN Special Co-ordinators Office's most senior representative in Israel, told the Herald that when Israel launched its surprise attack on Gaza on December 27, the UN's massive warehouses in Gaza were nearly empty, with all food and equipment sitting in nearby port facilities.

"The food was in Israel, but we couldn't get it in. This is before. The blockade was very tight."

As the Israeli Prime Minister, Ehud Olmert, halted the attacks, declaring that Israel had attained its goals following the lethal assault on Gaza that has killed more than 1200 Palestinians - a third of them children - and 13 Israelis, Hamas militants continued to fire rockets into Israel.

Five Qassam rockets slammed into the Israeli city of Sderot yesterday, with no reported injuries, just hours after Mr Olmert had announced a unilateral ceasefire that would be maintained as long as Hamas stopped firing rockets at Israel.

Mr Olmert said Israel would continue to occupy Gaza and was working with several international partners including the United States to prevent Hamas from re-arming by putting an end to its smuggling operations.

"Hamas was hit hard," Mr Olmert said. "Both its military capabilities and its governing infrastructure." Operation Cast Lead erupted in late December last year after Hamas declared that it would not extend a six-month truce with Israel that had expired on December 19.

Hamas leaders argued that it had no incentive to renew the truce because conditions had not improved during the months of calm.

According to Hamas, in return for stopping the rocket fire, Israel had promised to ease its blockade of Gaza and allow the passage of more food and commercial supplies.

"I think the expectation on the Israeli side was that the rockets would stop. Well, they nearly did. I think there were 40-odd rockets fired over four months roughly," Mr Gaylard said.

Before the truce there was a monthly average of several hundred rockets and mortar shells being fired into Israel.

"The expectation on the Gazan side … was that more supplies would be allowed in, and it didn't happen," Mr Gaylard said.

"In fact, we noticed, I think from 19 June for the next four or five months, or up to even 19 December, less of our supplies and spare parts and items of equipment, less got in than before the 19th of June."

Mr Gaylard slammed Israel's siege policy towards Gaza, which he said had strengthened the popularity of Hamas.

"It's difficult to understand the mentality of firing these rockets … it is equally hard to understand why the Israelis are strangling this place,' Mr Gaylard said.

"It is to cause Hamas to fall, but my experience of the last year of going in and out of Gaza and staying there, was that it had exactly the opposite effect.

"Hamas did not keep its commitments during the truce, they maintained the rocket fire and continued to attack Israeli technicians who were sent in to Gaza to repair various facilities."

Mr Gaylard, who is also the UN's deputy special co-ordinator for the Middle East Peace Process, said it would require several billion dollars and at least five years to repair the physical damage caused by the last three weeks of fighting.

As for the long-term goal of resolving the 60-year Israeli-Palestinian conflict, he said that had been dealt a severe setback.

Mr Gaylard urged the world to put more pressure on Israel to stop the growth of Jewish settlements in the West Bank, which he said Israel had pledged to do several times, most recently at the Annapolis Middle East Peace conference in November 2007.

"Palestinians are trying to meet their part of it … security has improved in these key West Bank towns, meanwhile, the settlements, I don't see any change," Mr Gaylard said.

Mr Palmor said it was unhelpful to pick on the settlements issue because it was just one part of the story.

"We are trying to conclude a global solution to the conflict, one that will resolve all the issues, including security, refugees, land and settlements," the Israeli spokesman said.