The Korean Grand Prix is only "50/50" for next year with local organisers counting on support from Formula One ringmaster Bernie Ecclestone, its promoter said.
First held three years ago in torrential rain, the grand prix has struggled to attract sponsors and crowds and it has only been provisionally pencilled in for next season.
Ecclestone, Formula One's commercial rights holder, brought the sport to the country but needs convincing the race, in a sparsely populated, rural area, is worth keeping.
The event had a stay of execution last year when he agreed to renegotiate the terms of the contract -- hence a banner signed by local authorities at this year's race reading: "Thank you, Mr. Ecclestone, for 2013 F1 Korean GP."
But the Formula One supremo may not be so generous this time.
"The possibility to hold the event (next year) is 50/50," acting promoter Park Won-Hwa told journalists ahead of Sunday's race.
"We have to negotiate with Mr. Ecclestone. I expect his support for our Korean GP to succeed. Mr. Ecclestone was the first person to introduce F1 to our country.
"We have to deal with Mr. Ecclestone. We expect his favours, but we do not know yet."
Since 2010 the Korean Grand Prix has been held in the autumn, a potentially decisive part of the season.
However next year's extended 22-race schedule, which is yet to be finalised, has it in April, immediately after China and before Spain.
"It is more helpful for teams and freight," said Park, a former diplomat. "It was Mr. Ecclestone's idea to hold it in the spring, in April."
One of the major criticisms levelled at the Korean Grand Prix is its location.
The coastal Yeongam circuit is in the remote southwest of the country and the nearest big city, Mokpo, is hours away from Seoul.
It had been hoped the race would bring visitors, investment and development to the sleepy region, but critics say that initiative has largely failed.
"If Korea does not have success, it is because the track is far from city centres and F1 is not known enough for Koreans," said Park.
"This is better now because we are in the fourth year. When I was offered the position I did not even know what F1 was."
Park admitted getting Korean sponsors was a struggle, but insisted it was "picking up".
"But for the moment the sponsors are not ready. Maybe they are scared by Mokpo or by F1," he said.
Park expects similar attendances to last season, including 80,000 people on race day, which would make it over half-full.
He admitted that an advertising campaign to attract fans had not been a great success, in a country where baseball and football dominate the sporting landscape.
Part of the problem was the price for tickets compared with other sports, he said.
Park added: "It would be much better to have the circuit in an area with a big population. But this is too late.
"The people wanted to hold an F1 event in this province (South Jeolla) to bring in spectators and make the province popular."
South Korea has a seven-year contract with a further option of five years, ostensibly taking the event up to 2021.