This was one of the key conditions of Iran being awarded the event, due to to take place in Kish Island, a 91.5 square kilometres resort in the Persian Gulf, from February 14 to 19.

Organisers had not been able to provide this guarantee until now, after a lengthy negotiating process, the FIVB said today.

"We've had confirmation from the organisers that the event will be open to fans from all age groups and genders," the body's communication director Richard Baker told insidethegames.

"This will include families and women."

A 27-year long rule banning women from attending football matches in the Islamic nation was controversially extended to volleyball in 2012.

The FIVB have not yet managed to orchestrate a complete lifting of the ban before the start of the tournament, however, a target they claimed to be "hopeful" of achieving after awarding the event to Iran last November.

They remain confident the ban will be fully lifted before this year's Olympic Games in Rio de Janeiro. 

"This is a significant stepping-stone," said Baker.

"We are now negotiating for women to be allowed to attend World League matches [scheduled to be held in Tehran in June]."

The ban gained worldwide publicity in 2014 following the arrest of British-Iranian woman Ghoncheh Ghavami.

Ghavami, arrested for "propaganda against the regime" after attending an FIVB World League match in Tehran, spent 151 days in the notorious Evin prison before she was released and charges were eventually dropped. 

The FIVB were initially criticised for a lack of action but vowed to work with Iranian authorities, and promised not to allocate any more events to the country until the ban was lifted.

Both the World League matches and the World Tour event were awarded in apparent violation of this decision.

FIVB general director Fabio Azevedo, the official responsible for negotiating with the Iranians, told insidethegames they were prioritising a carrot rather than a stick approach to apply pressure to the Iranians to change their approach, a method they still believe will prove successful.

Convincing Iranian President Hassan Rouhani, a relative moderate who has notably improved Iran's relations with the Western world and has also enhanced women's rights by appointing female Foreign Ministry spokespersons since he assumed office in 2013, is unlikely to prove too difficult.

The situation is complicated by the power still held by conservative religious figures, including Supreme Leader Ali Khamenei.

Criticism is bound to intensify if the ban remains in place by the time of Rio 2016, with Human Rights Watch having begun a digital advocacy campaign, #Watch4Women, seeking to end the ban and strengthen respect for women’s rights in Iran, "in line with international human rights standards and the Olympic Charter".

Only men will compete at the Kish Island event, a tournament among the lowest-level of World Tour competitions, but one which still offers vital Olympic qualification points.

Germany's Markus Böckermann and Lars Flüggen, ranked second in the 2015-2016 Tour rankings, are the leading entrants.

Fifty-four pairs spanning 22 nations are set to compete.