Cristiano Ronaldo has gone on strike ahead of Al-Nassr's next game in Saudi Arabia, according to a report in Portugal.

The 40-year-old superstar, who, on a contract worth £488,000 per day, is the highest-paid footballer in history, is reportedly dissatisfied with the management of Saudi Arabia's Public Investment Fund (PIF).

The Saudi Pro League giants are due to play local rivals Al-Riyadh on Monday but may now be without their captain, who has scored 18 goals in 22 games across all competitions this season.

According to Portuguese outlet A Bola, a source at the club told the newspaper that Ronaldo is unhappy with the manner in which Saudi Arabia's PIF is handling Al-Nassr's finances, particularly in comparison to how they are treating rival clubs.

The PIF controls a 75 per cent stake in four Saudi Pro League clubs — Al-Ahli, Al-Ittihad, Al-Hilal and Ronaldo’s Al-Nassr — and has been the driving force behind the league’s ability to attract some of world football’s biggest names on lucrative contracts. 

Shortly after Ronaldo's blockbuster move to the Riyadh club in 2023, the likes of Karim Benzema, Kalidou Koulibaly and Riyad Mahrez moved to Saudi Arabia on huge deals, joining Al-Ittihad, Al-Hilal and Al-Ahli respectively. 

Since then, all four teams have continued to bolster their squads, although Ronaldo, who is still yet to win a domestic trophy with Al-Nassr, believes his team have not been treated equally in the transfer market.

He claims Al-Nassr manager Jorge Jesus has not received adequate reinforcements compared to Saudi Pro League rivals Al-Hilal, who have been very active in the transfer market.

During the January window, the only player signed by Al-Nassr is 21-year-old Iraqi midfielder Haydeer Abdulkareem, while Al-Hilal have lured Spanish centre back Pablo Mari for £1.7m and spent a further £26m on Rennes forward Kader Meite. 

Simone Inzaghi's side are also reportedly finalising another £26m move for Neom star Saimon Bouabre.

Last month, Jesus called out the financial inequality and argued that Al-Nassr 'does not have the political power of Al-Hilal', a team he previously managed. His explosive remarks prompted Al-Hilal to request that the Saudi Pro League suspend Jesus for between six months and a year. 

In December, Ronaldo hinted at a possible return to Europe as he reiterated his ambition to reach 1,000 career goals.

Speaking at an awards ceremony in Dubai, the former Real Madrid and Manchester United forward said he was determined to 'keep going' at the top level.

'My passion is high and I want to continue. It doesn't matter where I play, whether in the Middle East or Europe,' Ronaldo said.

'I always enjoy playing football and I want to keep going. I will reach the number (1000 goals) for sure, if no injuries.'

The Portuguese icon scored his 961st career goal during Al-Nassr's 3-0 win over Al-Kholood last Friday.