Saudi Arabia's extraordinary football expansion is a "long-term project" with strong government support, unlike the short-lived Chinese boom, a senior league official told AFP.

The Saudi Pro League has a years-long commitment from the oil-rich kingdom's rulers in its goal to become one of the world's top competitions, chief operating officer Carlo Nohra said.

Nohra was speaking at Al-Hilal's unveiling of Brazilian superstar Neymar, who joins Cristiano Ronaldo, Karim Benzema and a host of other big names in a spending binge costing hundreds of millions of dollars.

"It's not something that we expect will happen overnight. It's not a one-weekend event -- this is a long-term project, and everybody accepts that that's what it's going to take," Nohra said at the King Fahd International Stadium late on Saturday.

"And it's not a function of throwing money at it and it will happen," he added. "It is ensuring that we do all the right things along the way to bring everything and everybody and the ecosystem up together."

The Saudi league's rapid expansion has drawn comparisons with the Chinese Super League, which sucked in players for exorbitant sums until clubs hit financial problems.

At one stage, Guangzhou Evergrande made little-known Argentine Dario Conca one of the world's best-paid players, and Shanghai Shenhua was lavishing a reported 730,000 euros ($795,000) a week on an ageing Carlos Tevez.

"These comparisons are inevitable," said Nohra.

"But for us, the fact that this project is part of a transformation project that's moving this country where it wants to go... provides the sustenance that we need in order to keep moving forward."

- 'No end to ambition' - 

The no-expense-spared revamp is part of 37-year-old Crown Prince Mohammed bin Salman's ambitious Vision 2030 project, which aims to reshape the economy of the world's top oil exporter.

Also part of the de facto ruler's plans are Neom, a futuristic new city costing $500 billion, plus tourist resorts and sports events including Formula One and the upstart LIV Golf, which has effectively seized control of the US PGA Tour and Europe's DP World Tour.

"Ultimately what we're really trying to do is deliver, through football, entertainment for the Saudis," Nohra said.

"The strategy is 360 degrees, many elements to it. At the heart of it, one of those objectives set for us is how do we improve performance on the pitch, with world-class sports performers."

Nohra said Pro League clubs -- including four recently acquired by the Public Investment Fund, a sovereign wealth vehicle -- were still on the hunt for players before the Saudi transfer window closes on September 20, three weeks after Europe's.

"There are clubs that are still in the market looking for players," said Nohra, calling their targets a "closely guarded secret".

Despite the enormous outlays -- Neymar's Al-Hilal is the world's second biggest-spending club this summer -- the budget is not bottomless, and the aim is for the teams to become financially viable and perhaps go private.

"There has been a (spending) limit set, yes, but we have understood from the outset, that in order to get the quality players that we need to come to make an impact here, we needed to pay a premium for that," Nohra said.

"We're fortunate enough to have the support at the moment, and that will continue for some time," he added.

"But we also have the responsibility to ensure that they cross the bridge to the other side and become financially independent as well."

Nohra said he was "definitely" confident the Pro League could become a top-five competition when measured by the quality of players, stadium attendances and commercial success.

"There is no end to kind of the ambition of the people here," he said, citing the Asian Champions League as a major target of the Saudi clubs.

"This strategy will continue to evolve over time. We'll correct course, we'll take a different shape as we feel we've arrived at a threshold that requires us to move to the next step."