John Kerry, US secretary of state, has arrived in Geneva, where he joins top-level diplomats from six other foreign nations for talks aimed at reaching a nuclear deal with Iran.

Saturday's meeting will be the second time in two weeks involving Kerry and other senior emissaries in the Swiss city after there intensive talks failed on November 10.

Kerry decided to go back for another try "in light of the progress being made" and "with the hope that an agreement will be reached", Marie Harf, State Department spokesperson, said on Friday.

He will be joined again by his French, British and German counterparts - respectively Laurent Fabius, William Hague and Guido Westerwelle - plus Russia's Sergey Lavrov, who arrived in Geneva on Friday.

China's Wang Yi had missed the previous gathering but will be present in Geneva today, Saturday, the report stated.

The talks "have reached their final moment", Chinese foreign ministry spokesman Hong Lei said, as Wang left Beijing early on Saturday morning.

However, Kerry's appearance has been reported would not necessarily mean the talks were close to a resolution but because it might be useful for the US secretary of state to be in the room with the other top diplomats working out these thorny issues.