Onion prices in the country reportedly fell more than 30 per cent today after the government banned exports to rein in the cost of the vegetable, a staple for Indians and sometimes a trigger for voter protests over inflation.

Prices had more than doubled in the past week due to a shortage caused by unusually heavy rain in growing areas as also other supply bottlenecks.

The agriculture ministry on Monday banned exports until 15 January, and said it would import onions from neighbouring Pakistan, as retail prices jumped to Rs80 per kg from Rs35 last week.

"The situation will be normal in two to three weeks. Onion prices rose because of rains in Nasik and other onion growing areas," agriculture minister Sharad Pawar told reporters on Tuesday. "The ban on onion exports should help reduce the prices," he added.

Average onion prices at the country's largest wholesale onion trading hub in Lasalgaon (western Maharashtra) fell 34 per cent to Rs2,500 per 100 kg after the ban.

"Restrictions on exports today pulled down prices in the wholesale market. They will fall further in the next few days in the wholesale and retail markets," R P Gupta, director at the National Horticultural Research and Development Foundation (NHRDF), told media.

Food price inflation has retreated over the past three months, but the climb-back to a high 9.5 per cent is a worry for the ruling Congress party ahead of elections in several states next year.

On Monday, Prime Minister Manmohan Singh told his party at a plenary meeting that inflation "remains a cause for serious concern in our country".