Iranian diplomats are in Saudi Arabia to start work at a global organisation representing Muslims, a first since the two rivals cut ties in 2016, Iran's foreign ministry announced on Monday.

"The delegation is now in Jeddah to start its work at the Organisation of Islamic Cooperation," Saeed Khatibzadeh said in his weekly press conference.

This "can be a good prelude for the two sides to send delegations to visit their embassies," he added.

Shiite-majority Iran and the Sunni Kingdom of Saudi Arabia are both members of the pan-Islamic body of 57 member states. The two regional rivals have so far held four rounds of talks since April aimed at improving relations. 

"We have given our written points of interest to the Saudi delegation at the fourth round of negotiations in Baghdad and we are awaiting the responses," Khatibzadeh stressed.

Riyadh and Tehran support opposite sides in several conflict zones across the region including in Syria and Yemen.

In 2016, the kingdom's execution of revered Shiite cleric Nimr al-Nimr saw protesters attack Saudi diplomatic missions in Iran. Riyadh responded at the time by cutting ties with Tehran, while OIC foreign ministers condemned the violence.

Khatibzadeh reiterated Iran's position that Tehran is "ready to open its embassy" but that depends on what "practical steps" Saudi Arabia takes.

In December, foreign ministry officials in both countries said the kingdom had granted visas to three Iranian diplomats to the OIC.

The Organisation of Islamic Cooperation describes itself as the collective voice of the Muslim world.