"We hope it will be before the end of the Iranian calendar year," Araghchi told reporters in Vienna, referring to March 20 when the Iranian year ends.

Araghchi was in the Austrian capital for a "joint commission" with representatives from China, Russia, Britain and France -- all signatories of the international deal on Iran's nuclear programme.

The new payments vehicle, known as INSTEX, is seen as key to European Union efforts to preserve the deal struck in 2015 between world powers and Iran over its nuclear programme, the Joint Comprehensive Plan of Action (JCPOA).

The US was also initially a signatory but last May US President Donald Trump withdrew from the deal and in November imposed sweeping new sanctions on Iran.

Araghchi said there was "very strong support" for the deal from all participants at the meeting.

He said the director of INSTEX was due to visit Tehran "very soon in order to have closed discussions" with his Iranian counterparts.

"An Iranian mirror structure is going to be established very soon and these two structures will work with each other," he added.