The WTO's regular Trade Policy Review of Japan said the overall level of government assistance for agriculture was "well above" the average for industrialised countries in the Organisation for Economic Cooperation and Development (OECD).

The report also found that average import tariffs in agriculture had increased, from 17.7 percent in 2004 to 18.8 percent last year.

Japanese authorities paid out almost as much to the farming industry as the sector contributed to the economy, according the report.

Payments to farming were equivalent to 1.3 percent of gross domestic product (GDP) in 2004, compared to agriculture's 1.4 percent share of GDP.

Rice, wheat and barley were thought to be the most heavily supported, but the WTO's secretariat said it was unable to obtain fresh data on the amount of subsidies for rice, a staple food in Japan.

Japanese authorities are planning to move further away from supporting prices for domestic produce -- which is regarded as a trade-distorting form of subsidy -- to more trade-friendly income support, the WTO acknowledged.

"However, the sector remains relatively protected from foreign competition," it added.

Trade policies for the country's flagship manufacturing sector remained largely commerce-friendly, the report said.

"Japanese manufacturing has, by and large, been much more exposed to international competition than agriculture and certain services," it added.

Overall, the global body underlined a favourable outlook on Japanese trade policy, saying several measures had been introduced since the last report two years ago to open the economy even more to foreign competition.

Most imports enter Japan free of duty or with low tariff rates, which are kept at largely predictable levels, the report said. Most of the "few" non-tariff barriers used by Japan are on imports of fish, another local staple.

Japan was the world's fourth-largest exporter and importer of goods in 2005.

The Japanese government said in its report to the WTO that it had not made any significant change in its trade policy since the last review, emphasising that it was a "firm supporter" of the global free trade system.

The reports are being examined at a meeting of the WTO's 150 members until Friday.