TOKYO—Japan's core consumer price index fell 0.3% from a year earlier in February, the government said Friday, marking the 24th straight month of decline as deflation persisted amid continued sluggish domestic demand despite rising commodity prices.

Analysts say it is uncertain how the devastating earthquake and tsunami that struck northeastern Japan on March 11 will affect prices ahead.

The reading from the Ministry of Internal Affairs and Communications matched the median forecast for a 0.3% drop in a poll of economists by Dow Jones Newswires and the Nikkei. It exceeded the 0.2% fall in the previous month.