The confidential talks, involving diplomats and experts from Britain, France and Germany, as well as Iran, are due to last three days, the diplomat added.
The new round of meetings is taking place amid Iran’s continued rejection of a demand to permanently abandon uranium enrichment, a fuel process which can assist in the functioning of nuclear power stations but also produces material for nuclear weapons.
The United States maintains that Iran is trying to covertly develop nuclear weapons, while Tehran insists that its programme is purely meant to fill civilian energy needs.
The diplomat said the first day of talks would focus on political cooperation, with the key nuclear issue only due to be broached on Wednesday and Thursday.
The Europeans have held several meetings with Tehran since December to try to persuade Iran to guarantee that it will dismantle nuclear fuel work in return for technical assistance and economic and political rewards.
The four-party technical talks this week in Geneva are scheduled to be the last round of technical talks before a meeting of a higher level steering committee at the end of March.
Iran’s top nuclear official Hassan Rowhani warned Saturday that his country would never agree to a permanent halt on enriching uranium.
“We cannot have and we will not have negotiations with the Europeans if what they want is an end” to uranium enrichment, Rowhani told reporters in Tehran.
Iran agreed in November to suspend enrichment as a “confidence building measure” to show its intentions are peaceful, but has stressed the halt would be temporary.
