ABU DHABI (REUTERS) - Formula One races in Mexico and New Jersey are unlikely to happen next year, the sport's commercial supremo Bernie Ecclestone told Reuters on Sunday.

Both events were on a 22-race calendar published in September but the 83-year-old, speaking at the Abu Dhabi Grand Prix, doubted they would stay on a final version due to be approved by the sport's governing body next month.

"I would doubt whether it's going to happen," the British billionaire said when asked about New Jersey, whose debut has already been postponed once.

That June 1 race is listed as part of a "triple header" on successive weekends in between Monaco and Canada.

"It's not definite that it will or won't (go ahead) but I doubt that it does," said Ecclestone.

Mexico, whose race is scheduled for Nov 16 as the penultimate round of the season at Mexico City's Hermanos Rodriguez circuit, also has an asterisk against it on the provisional calendar.

"Definitely not," said Ecclestone before correcting himself: "Probably not."

Formula One has never had more than 20 races in a season, with this year's calendar running to 19 rounds.

If Mexico and New Jersey fail to make the final version, the main novelties will be Austria - returning in June after a decade off the calendar - and a new race in Russia's Winter Olympic venue Sochi in October.

India has been dropped for 2014 and South Korea's race remains doubtful with the local organisers seeking a contract renegotiation for the loss-making event.

Mexico last hosted Formula One in 1992 but recent media reports have suggested the time frame is too tight to make the necessary improvements to the outdated facilities and a postponement to 2015 looks more realistic.

New Jersey, whose "Grand Prix of the Americas" would have been the second US race on the calendar along with Austin, Texas, and held against a backdrop of New York's Manhattan skyscrapers, has struggled with finances.

It was due to make its debut last year but had to be postponed. It was absent from a draft calendar circulated to teams earlier in the year and then reinstated despite considerable scepticism in the paddock.

Ecclestone was quoted by CNN in August, before the race was added to the calendar, as saying New Jersey was "not on the cards" because the organisers "haven't got any money".

Team managers said last month the race would pose an almost impossible logistical challenge if it were to go ahead in its current slot.