* First NEOM phase to cost $319 bln, partly funded by wealth fund

* Project to have capacity to house nine million by 2045

* Aims for Saudi stock exchange to be in world's top three (Updates with details, quotes)

By Yousef Saba

JEDDAH, Saudi Arabia, July 26 (Reuters) - Saudi Arabia's Crown Prince Mohammed bin Salman said on Monday his $500 billion flagship project NEOM, a huge economic zone eventually meant to house nine million people, will be partly financed through a flotation expected in 2024.

The city's first phase is set to cost 1.2 trillion riyals ($319 billion), half of which will come from the kingdom's sovereign wealth fund, the Public Investment Fund, he said.

The crown prince was speaking to reporters, architects, investors and others on Monday attending a presentation that provided updates on The Line project, a key part of the NEOM development.

Saudi Arabia will tap sovereign wealth funds in the region and globally in the fourth quarter of this year to raise part of the remaining 600 billion riyals, which will also be funded through private sector investment and an initial public offering (IPO) that is expected to take place in 2024, he said.

Saudi Arabia will also allocate 300 billion riyals for a fund linked to NEOM, which will invest in companies that set up there.

The crown prince announced plans for NEOM in 2017 as part of his Vision 2030 reform plan, which aims to diversify Saudi Arabia's economy away from oil.

The kingdom's sovereign wealth fund is the cornerstone investor in NEOM, a 26,500-square-km (10,230-square-mile) high-tech development on the Red Sea with several zones, including industrial and logistics areas.

NEOM is expected to have capacity for 450,000 people by 2026 and 1.5-2 million people by 2030, eventually housing nine million by 2045, the crown prince said. The interim goal would make the city bigger than Abu Dhabi, he said.

Asked why the development was needed, he said it was central to Saudi Arabia's ambitious population-growth goals and its ability to compete globally.

"NEOM will add a trillion riyals to the Saudi stock market value. At least 1.2 trillion in the beginning and the overall will increase after project completion to exceed 5 trillion," he was quoted as saying on state-owned al-Ekhbariya TV.

At the presentation for The Line, he said Saudi Arabia aimed for its stock exchange to be among the three biggest in the world.

Middle East and North Africa issuers - mostly in the Gulf - raised over $13.5 billion via IPOs in the first half of this year, the bulk in Saudi Arabia, Refinitiv data showed.