Though SoftBank Group insists that plans to build the world's largest solar farm in Saudi Arabia are moving forward, doubts remain about a project key to CEO Masayoshi Son's international energy business strategy.

The Japanese company rejected a report by The Wall Street Journal that the $200 billion solar power plant had been put on hold, saying on Tuesday that "progress continues to be in line with expectations for a project of this scale and complexity."

SoftBank added that it and its partners would provide an update on that progress in the coming months.

The massive solar farm would have turned Saudi Arabia, the most important oil producer in the world, into a solar power giant.

The report follows Saudi Arabia's decision to put off plans to list state-run oil company Saudi Aramco, a proposal regarded as the centerpiece of Crown Prince Mohammed bin Salman's efforts to wean the economy off petroleum.

This and other signs point to an unstable balance of power within the Saudi royal family, which is troubling for Son as the Saudi government is the biggest investor in SoftBank's $100 billion Vision Fund.

The 33-year-old Mohammed has challenged decades-old traditions in the kingdom by permitting women to drive and allowing theaters to open, trying to transform the country into a more attractive destination for investment. He also has undertaken an aggressive foreign policy, confronting regional rival Iran and conducting expensive military operations in neighboring Yemen.

The Journal cited a Saudi energy official as saying, "Everyone is just hoping this whole idea would just die," regarding the proposed solar plant, which is intended to generate up to 200 gigawatts by 2030.

Yet Son has good reason to fight for the project, which represents part of his vision to build a solar power generation network across sun belt countries like Saudi Arabia and India. That electricity would supply the rising demand for power in Europe, Asia and elsewhere.

Son met with Rwandan President Paul Kagame and African Union officials in Mauritania in July to discuss solar energy investments on the continent. The company also has proposed plans to India's government for solar investments there.

The SoftBank chief has long envisioned an international power network. In 2011, he proposed the creation of an Asian "super grid" that would send renewable energy such as wind power from Mongolia to Japan, China and other energy consumers.

This vision is proving slow to translate into reality, however, owing partly to a lack of legislation in Japan and South Korea to govern the international pooling of electricity.