TEHERAN (AFP) - Iran's tactics in talks on its nuclear programme with the major powers have been "flawed" under the current negotiating team led by Saeed Jalili, presidential election candidate Ali Akbar Velayati said on Friday.

"The current negotiations that are under way are definitely flawed," said Mr Velayati, a conservative former foreign minister who is standing against Mr Jalili in the June 14 election.

Mr Velayati served as Iran's top diplomat for 16 years before being appointed an adviser to supreme leader Ayatollah Ali Khamenei, who has the final say on nuclear policy.

The nuclear programme has for years been a point of contention between the Islamic republic and the P5+1 countries of Britain, China, France, Russia and the United States, plus Germany amid suspicions that it is cover for a weapons drive.

Mr Velayati made the remarks at a live televised debate, the last of three, which finally produced some heated exchanges between the eight candidates approved by the hardline electoral watchdog from a field of nearly 700 would-be hopefuls.

Known for his tough stance since he took over as Iran's nuclear negotiator, Mr Jalili has vowed to pursue the same tactic of "resistance" if elected president.

Mr Velayati said the approach had cost Iran unnecessarily damaging international sanctions. "Diplomacy is not only roughness and hardiness. It is bargaining," he said.

"The art of diplomacy is that we save the nuclear right, while at the same time, we reduce the sanctions."

The European Union and the United States have both imposed tough unilateral sanctions on Iran's oil and banking sectors over and above the measures adopted by the United Nations, dealing a heavy blow to the economy.

Mr Jalili's negotiating style has also come in for criticism from another fellow candidate Hassan Rowhani, who headed the relatively moderate nuclear negotiating team that served under reformist president Mohammad Khatami in the early 2000s.