The announcement comes as Japan prepares to host the summit of the Group of Eight wealthy nations next week, with an agenda that will be dominated by soaring food and fuel prices, as well as climate change.

"Since the situation remains serious in developing countries, we will donate another $50 million in food aid, adding to the $200 million we have already implemented or announced," the foreign ministry said in a statement.

The aid will be distributed by October, the ministry said, bringing Japan's food and agriculture-related aid to a total of $1.1 trillion since the beginning of the year. Much of that was announced at a conference of African leaders hosted by Japan in May.

The World Bank said in a report this week that 73 million people could be tipped into poverty by rising food prices alone. Grain prices have more than doubled since January 2006, while rice prices more than tripled between January and May 2008, it said.