"Refusing a German development minister entry to the Gaza Strip is a great foreign policy mistake on the part of the Israeli government," Niebel told the online edition of the Leipziger Volkszeitung newspaper. "I am saddened that Israel is making it so difficult for its truest friend to understand its actions."

Niebel wanted to visit the Hamas-run Palestinian territory Sunday to meet representatives of the United Nations Relief and Works Agency for Palestine refugees.

German Foreign Minister Guido Westerwelle said in a statement in Berlin that he also "regretted" the decision by the Israeli government, and underlined that Germany and the European Union want to see an end to the Gaza blockade.

Israel maintains that the blockade — imposed when one of its soldiers was captured by Palestinians in a June 2006 cross-border raid and tightened a year later when Hamas took over the territory — is needed to ensure its security.

Niebel said time was running out for Israel to move away from hard-line policies in light of international protests over its Gaza policy and faltering efforts to achieve a viable peace deal with the Palestinians.

"For Israel, it is five minutes to 12," he said, adding that the country must take the opportunity "to stop the clock while it can."

"If the Israeli government wants support for its new Gaza strategy then it must ensure more transparency and a new partnership," he said. The blockade "is not a sign of strength but rather evidence of unspoken fear."

The deputy leader of Chancellor Angela Merkel's Christian Democrats' parliamentary group, Andreas Schockenhoff, said Israel was only "hurting its own interests" with such moves and demanded "unfettered access" to Gaza for international guests and officials.

On Sunday, Israel said it would "as quickly as possible" publish a list of banned goods, and that all items not on the list would be allowed into Gaza. Prime Minister Benjamin Netanyahu announced the plan together with international Middle East envoy Tony Blair, who had been lobbying Israel to restrict its embargo to a list of specified items.