April grands prix in Bahrain and Saudi Arabia (Jeddah) were both called off due to the Iran war , but attempts to reschedule a round in Bahrain had looked promising until the situation flared up again.
Multiple sources at the Hungarian Grand Prix told Reuters there were a number of replacement options being looked at, with nothing decided, but Malaysia's Sepang circuit was one of those on the list.
A likely slot would be between Baku on September 26 and Singapore on October 11.
Malaysia last hosted a Formula 1 Grand Prix in 2017 but has remained on the MotoGP calendar and is of the grade required by the FIA. State oil company Petronas is also a partner of current Formula 1 leaders Mercedes.
Another alternative in the Asia region was Japan's Suzuka circuit, but one source said there was less appetite from teams to return there for a second time this season.
The Middle East is due to host the year's last two races in Qatar and Abu Dhabi in late November/early December, and while they remain scheduled at present, there is lingering uncertainty.
For logistical reasons, any decision on a replacement for Bahrain would need to be taken before the August break, which follows Sunday's race at the Hungaroring.
The FIA's World Motor Sport Council is due to vote this weekend on postponed World Endurance Championship (WEC) rounds scheduled for Bahrain and Qatar in October and November, with the expectation that they will be moved to European circuits. Formula 1 is understood to be awaiting the outcome of that vote.
Portugal's Portimao circuit, due to return next season as part of a two-year deal, has also been touted as a likely host to increase the number of races should Qatar and Abu Dhabi be forced to drop out, while Barcelona may also be an option.
Given the warmer climate in Portugal's Algarve region, the circuit near Faro is seen as one of few in Europe able to host Formula 1 in the winter months.
Formula 1's 2026 season was originally scheduled as a 24-race championship and the addition of replacement races would satisfy broadcast deals and could bring the number back to 22 or 23.