The Finn's comeback deal with Lotus was initially a two-year contract, expiring at the end of 2013.
Speaking as Lotus launched its new E21 chassis, Raikkonen said he had not given much thought to the future, but was sure he would stay on if he continued to enjoy F1.
"I'm not really thinking beyond this season at the moment, but I'm sure there will be talk before the end of the year," he said.
"I enjoyed my comeback to Formula 1 last year and there's no reason to say I shouldn't enjoy the 2013 season too.
"I know there will be big changes to the cars and regulations for 2014, so who's to say that won't be exciting."
Raikkonen initially walked away from the sport when he left Ferrari at the end of 2009.
He switched to the World Rally Championship with Citroen, but struggled for consistent form. Despite forays into the NASCAR Truck Series and a test in Peugeot's Le Mans contender, he ultimately returned to F1 with Lotus.
Lotus E21 launch - full coverage:
Lotus reveals the E21
Raikkonen sure Lotus capable of titles
E21 unveiling gallery
Lotus keeps passive double DRS
Valsecchi becomes Lotus third driver
Why Lotus was right to keep Grosjean