The speaker of Iran's parliament said Wednesday he was looking forward to fresh nuclear talks next week with a positive attitude amid hopes the new leadership in Tehran could herald a breakthrough.

Ali Larijani, a former top Iranian nuclear negotiator, told reporters: "A handful of countries were levelling threats at my country, they are looking now for a political solution, I see it as a positive step."

"I look at the coming negotiations positively," added Larijani, ahead of talks between Iran and six world powers -- Britain, China, France, Germany, Russia, the United States -- in Geneva starting Tuesday.

The latest round in the long-running negotiations will be the first since the election in June of President Hassan Rouhani, widely seen as a moderate.

Rouhani has come out strongly in favour of a quick deal after negotiations over the nuclear programme practically stalled for eight years.

Iran's US-educated foreign minister, Mohammad Javad Zarif, has said he hopes to reach a settlement within a year and will present a package during the October 15-16 talks.

Larijani described the talks as "a window of opportunity (to solve the problem) provided the parties can use it."

"To build confidence you need to take a lot of steps, you need to have a plan," said Larijani, adding that he expected the talks to be "very serious."

"It's not a commercial deal, it mostly concerns building confidence," he added.

The West and Israel accuse Iran of seeking to develop nuclear bombs in the guise of a civilian programme, charges Tehran has always denied.

Asked about Washington's stand that the use of force to stop Iran's programme was not off the table, Larijani said that "when it comes to Iran nobody gives that much value to such threats".

Iran wants an easing of a raft of UN and Western sanctions targeting its vital oil exports that last year began to cause major economic problems.

But US Secretary of State John Kerry on Monday urged Iran to come up with new nuclear proposals to unblock the long-running impasse.