Saudi Arabia is to officially appoint Aiman al-Mudaifer as the chief executive of NEOM, the $500 billion mega-project at the heart of the kingdom's drive to diversify away from oil, two sources familiar with the matter said on Tuesday.

Mudaifer has been NEOM's acting CEO since November, succeeding Nadhmi al-Nasr, the long-time former chief of the Red Sea urban and industrial development project that is nearly the size of Belgium.

Saudi Arabia's wealth fund PIF was not immediately available for comment.

The kingdom, the world's top oil exporter, has been facing mounting pressure to cut spending or raise debt after a plunge in crude prices, complicating plans to fund its expensive agenda to wean its economy off hydrocarbons dependence.

Crown Prince Mohammed bin Salman, known as MbS, has been pouring hundreds of billions of dollars into development projects via the PIF, with NEOM being central to his Vision 2030 plan to create new engines of economic growth beyond oil.

But some of the projects have had to be downsized due to rising costs, including The Line, a futuristic city between mirrored walls extending 170 km (106 miles) into the desert within NEOM, which is due to house nearly nine million people.

One of the sources said that Mudaifer, who will be appointed in the coming weeks, has deep knowledge of NEOM and has been involved in PIF monitoring the mega-project's developments for some time. The source added that this was a sign that PIF is taking greater oversight over NEOM.

Mudaifer, who led the Local Real Estate Division at PIF since 2018, was assigned last year with overseeing the operational continuity of NEOM, which has seen some of its schemes scaled back.

At his role in PIF, al-Mudaifer oversaw all local real estate investments and infrastructure projects, and he is a board member of several prominent companies in the kingdom, NEOM said in November.

(Reporting by Pesha Magid in Riyadh and Federico Maccioni in Dubai, Writing by Nayera Abdallah, Editing by Louise Heavens and David Evans)