The fifth and sixth rounds of the world championships in Portugal and Sardinia have been cancelled after round four in Mexico was cut short because of the health crisis last month.
Frenchman Ogier, who leads the drivers' standings, is hoping to compete in Finland in August.
"I don't think we will be able to restart before Finland in August and that's the most optimistic scenario," the Toyota driver told French sports daily L'Equipe on Thursday.
The next race on the calendar is in Kenya from July 16-19 but the East African country has cancelled flights and barred entry to people from countries affected by the outbreak.
Ogier also believes some races will not be held because of the high travel costs.
"All the costly trips (to New Zealand or Japan) will be complicated because the constructors will be badly hit by the situation and measures will have to be taken to cut costs," he said.
"I hope it will be possible to have five other rallies but I have no idea." (Reporting by Julien Pretot; Editing by Toby Davis)