YEONGAM, SOUTH KOREA (REUTERS) - Pirelli plan to be Formula One's sole tyre supplier for the next five years but a new contract with the governing FIA has yet to be signed, the Italian company's motorsport director Paul Hembery said on Friday.

The International Automobile Federation said last week that Pirelli, whose existing contract expires at the end of the season, could continue through a "transition period" before any eventual tender.

It gave no time period but Hembery told reporters at the Korean Grand Prix that "we are working on five years".

Pirelli have agreements with the 11 teams and commercial rights holder but Hembery said the final contract with the FIA could take some time to complete.

"Bear in mind that when we came into the sport (in 2011) it (the initial contract) wasn't signed until February of the year in which we started racing. There's meetings still going on,"said the Briton.

"Unfortunately. When you've got lots of different groups involved and lots of different lawyers there's lots of details but the principles are all working."

Hembery said there was absolutely no anxiety on Pirelli's part about the situation.

"There might be more anxiety from the other people's point of view because we could walk away," he said.