A leading human rights charity has urged the International Volleyball Federation (FIVB) to stop awarding its tournaments to Iran until the country allows women into its stadiums.

Female spectators have been banned from attending volleyball matches in the Islamic Republic since 2012, with several women arrested in 2014 for attempting to attend the Volleyball World League match at Azadi Stadium.

In a letter to Ary Graça, the sports federation's leader, Human Rights Watch urged the FIVB not to allow Iran to host the World League or beach tournaments - which the country is currently competing to host - given the stadium ban for women.

The charity also suggested the FIVB had broken its promise to make tickets available to women during a July tournament, when FIVB alleged it had sold 466 tickets to a women-only stand but video footage of the matches showed the majority of seats in that stand were empty - allegedly because the tickets were not offered by Iranian authorities for public sale.

"Iranian volleyball authorities broke their promises to make tickets freely available to women during the World League matches in July and suffered no consequence," said Minky Worden, Director of Global Initiatives at Human Rights Watch.

"Awarding Iran yet another World League tournament would only embolden the authorities in their discriminatory policies that sideline women."

"Despite its pledge to end discrimination in the stadiums, the Iranian volleyball federation appears to have constructed a system that denies most women any opportunity to attend matches," Worden added.

"The FIVB should make clear that Iran will not be able to host international volleyball competitions until the Iranian federation makes good on its promises. The FIVB may want to build the sport of volleyball in Iran, but embracing gender discrimination and ugly double standards is no way to go about it."

The FIVB has not immediately responded to IBTimes UK's request for comment.