SEOUL, May 2 (Reuters) - South Korea's consumer inflation eased in April for the first time in three months, official data showed on Thursday, coming in lower than market expectations.

The consumer price index stood 2.9% higher than the same month the year before, compared with a rise of 3.1% in March and a 3.0% gain tipped in a Reuters survey of economists.

It was the slowest annual rate since January, according to Statistics Korea.

The index was flat on a monthly basis, after rising 0.1% in March, while economists had expected a median 0.15% rise. (Reporting by Jihoon Lee; Editing by Jacqueline Wong)