Israel continues to bar construction material from entering Hamas-ruled Gaza as part of an overall blockade of the territory.

The UN Development Program said in a report Sunday that Gazans have carried out small-scale repairs worth $173 million with recycled rubble or material smuggled through border tunnels. But thousands of homes, businesses and schools have not been reconstructed or repaired, said the report, citing Israel's three-year border blockade.

The findings show that the international community has been largely ineffective in addressing the needs of Gazans, said the top UNDP representative in the region, Jens Toyberg-Frandzen.

"In view of the scale of the needs, international assistance in Gaza is tantamount to tinkering on the edges," he wrote. "Maintaining the status quo will not enable Gaza to recover, and certainly not with the support of the international community, irrespective of intentions." Israel launched a three-week military offensive against Gaza's Hamas rulers in December 2008, in an attempt to halt years of rocket fire from Gaza on Israeli border towns. The war killed about 1,400 Gazans, along with 13 Israelis. More than 6,200 homes, hundreds of businesses, as well as dozens of schools and clinics, were destroyed or damaged, according to UN figures.

The blockade, imposed by Israel and Egypt after the Hamas takeover of Gaza, has significantly hampered rebuilding.

Israel only allows what it defines as "humanitarian goods" into Gaza, including foods and medicines. Most construction materials, such as steel and cement, are banned because Israel argues they could be used by Hamas for military purposes.

At the same time, much of the $1.3 billion in reconstruction aid pledged by the international community after the war has not materialized, in part because donors don't see a point in sending money as long as the blockade persists, UNDP officials said.

About $527 million would be needed just to rebuild the war damage, the UNDP report said.

UN agencies haven't been able to do much since they have no access to smuggled goods. Israel says it provides some cement and other goods for UN projects in Gaza, but the report said it falls short of meeting the needs of Gaza.