Israeli Prime Minister Benjamin Netanyahu on Wednesday expressed concern ahead of the next round of talks between Iran and the international community over Tehran's controversial nuclear programme.

"This model of a country talking, but at the same time developing nuclear weapons; threatening and at the same time developing nuclear weapons and threatening the use of nuclear weapons, we cannot allow this to happen in Iran," a statement from Netanyahu's office cited him as saying.

The Israeli premier was speaking during a meeting with visiting Norwegian Foreign Minister Espen Barth Eide.

"There are many issues in the Middle East, the issues between us and the Palestinians and our quest for peace, there are regional issues but I think they will be overshadowed if Iran believes it has a licence to develop atomic weapons" and continues weapons development, he said.

"We have to make sure this doesn't happen."

The statement quoted the Norwegian foreign minister as saying Oslo, which is on the board of UN nuclear watchdog the International Atomic Energy Agency, was also concerned.

"We are really concerned about the lack of cooperation and the fact that we're allowed to go to the irrelevant sites but not to the sites we want to see," it cited him as saying.

Officials from the so-called P5+1 grouping meet negotiators from Iran in Kazakhstan on Friday, hoping for a response to a revised offer that would ease some sanctions in return for concessions over its uranium enrichment activities.

The P5+1 groups the five permanent members of the UN Security Council plus Germany.

EU foreign policy chief Catherine Ashton said on Wednesday she was cautiously optimistic about the talks, hoping for a response to a revised offer that would ease some sanctions in return for concessions over Tehran's uranium enrichment.

The West suspects Iran of trying to develop a nuclear bomb, and has demanded that it halt uranium enrichment in return for an easing of the tough UN sanctions which are crippling its economy.

Iran rejects the allegations and demands the right to develop a civilian nuclear programme for peaceful energy needs.

Neither the United States nor Israel has ruled out military action against Iran's nuclear facilities.

Israel is widely believed to be the Middle East's sole nuclear-armed power.