Mohammed Al-Jadaan said there were "a lot of opportunities" in Iran and that he couldn't see any reason to prevent investments taking place between the two Gulf heavyweights.

"I would say quickly," he told the Financial Sector Conference in Riyadh, when asked how soon Saudi Arabia could start making "significant" investments in Iran.

"When people really stick to the principles of what was agreed, I think that that could happen very quickly."

The positive sentiment comes after Riyadh and Tehran announced, March 10, that after seven years of severed ties, they would reopen embassies and missions within two months and implement security and economic cooperation agreements signed more than 20 years ago.

The oil-rich rivals, who are on opposing sides in conflicts across the Middle East, severed relations in 2016 after Saudi's execution of a Shia cleric triggered violent protests.

Iran has been under renewed US sanctions since then president Donald Trump abandoned a landmark nuclear agreement between Tehran and major powers in 2018. Saudi Arabia, a longtime US ally, has said it supports the sanctions, which target key areas, including oil.

But Al-Jadaan said: "There is no reason for (investments) not to happen. I mean, Iran is our neighbour and has been and will continue to be for hundreds of years.

"So I don't see any issue that would prevent the normalisation of the relationship across investments... as long as we stick to the agreement, you know, respecting sovereign rights, not interfering in other affairs."

He added: "I think that there are a lot of opportunities in Iran, and we provide a lot of opportunities for them."