The warning came in an analysis which highlighted both the "opportunities and challenges" of hosting the later edition, but stopped short of recommending which one would be the best to target.

It followed the publishing of the International Olympic Committee (IOC) Evaluation Commission report on Wednesday (July 5) analysing the respective 2024 credentials of Los Angeles and its sole rival Paris.

An Extraordinary IOC Session here on Tuesday and Wednesday (July 11 and 12) is expected to rubber-stamp an Executive Board proposal to awarding both the 2024 and 2028 Games on September 13 in Lima.

Los Angeles is currently seen as more likely to host the later edition.

"Four more years would mean more time for Los Angeles to complete its ambitious public transportation infrastructure plans, which would help achieve the Games’ transit goals," the independent LAO report warned.

"Some also have suggested that the IOC could 'sweeten the deal'' by providing more money to the 2028 host.

"More IOC money could reduce Games budgetary risks and/or fund more youth sports activities in Southern California, but others have suggested such a deal is not feasible for the IOC.

"On the other hand, four more years means there is a possibility that some existing venues will not be available or viable as the needs of Olympic sports evolve."

It is pointed out that the velodrome in Carson - for which "extensive planned upgrades" might occur before the Games - opened just 13 years ago, which "shows that major upgrade needs could be identified at some facilities between now and 2028".

The report added: "There is a possibility, furthermore, that the Olympic and Paralympic programme of events will change more with the passage of four more years - with events added or dropped - necessitating further changes in the Los Angeles venue plan (beyond those event changes that might already occur between now and 2024).

"Finally, with the Games funded largely by broadcast contracts, corporate sponsorships, and ticket revenues, there is the possibility that the Olympic brand will become less popular over time, reducing the amount of money flowing into IOC and Olympic organising coffers."

Los Angeles Mayor Eric Garcetti has said that the city could request youth sport funding "right now" from the IOC in return for hosting in 2028.

But IOC President Thomas Bach and other key officials have publicly claimed they will not be prepared to do this.

The independent LAO also welcomed the general praise with which the IOC reacted to the "low risk" American bid in the IOC Evaluation Commission report before dwelling on some of the challenges identified.

This included the importance of meeting planned targets to improve the city’s transportation network, as well as the ambiguity of how much some privately developed venue will cost and the need to clarify coordination between organisers and public authorities.

"Like other observers, we think that Los Angeles’ bid is a role model for future Olympic and Paralympic host cities" they conclude.

It is recommended that the State Legislature focus its oversight work on two specific areas.

These concern "encouraging Games organisers and other public officials to stick with the bid plan to keep Games-related costs low" and "ensuring that the state executive branch is helpful to Games organisers in their efforts to deliver a successful Olympics and Paralympics for athletes and spectators alike".

A decision to host in 2028 rather than 2024 would require a reassessment of the guarantees issued by the state authorities, it is warned.

"If Los Angeles hosts the 2028 Games and the state provides a backup financial guarantee, there will still be a need for the same type of legislative oversight we have recommended for 2024," the report concluded.

"In any event - 2024 or 2028 - the Legislature, in its oversight role, can help ensure this Governor, the next Governor, and their executive branch departments further the goal of hosting a third successful Summer Olympics in Southern California."

Both Los Angeles and Paris’ bids are due to showcase themselves to the full IOC membership for the first time here in a closed Candidate City Briefing also scheduled for July 11 and 12.

The full California LAO report can be read here.