Sanctions on Iran over its contested nuclear programme are biting but need to be strengthened further, French President Francois Hollande and his Israeli counterpart Shimon Peres said on Friday.

Western powers suspect Iran's nuclear programme to be a cover for building an atomic weapons capability, a charge which Tehran strongly denies.

"I have said how much we want the sanctions to be beefed up, which are already efficient," Hollande said after meeting Peres.

Iran last month held talks with the five UN Security Council permanent members -- the United States, China, Russia, Britain and France -- plus Germany on its nuclear ambitions in the Kazakh capital Almaty.

The meeting saw the group offer Iran a softening of non-oil or financial sector-related sanctions in exchange for concessions over the country's uranium enrichment operations.

"The sanctions are effective more than we thought but not enough... and I was very glad to hear from the president (Hollande) that he plans to take more measures because if we can end this danger without military use, it will be better," Peres said.