The government will launch an investigation into three farm products to determine whether import restriction measures are needed to protect domestic producers, it was announced Tuesday.

The agriculture, finance and international trade and industry ministries will start the joint probe this week on imports of leeks, fresh mushrooms and rush, which is woven into tatami. Most imports of these three products come from China, according to a MITI official.

The government is empowered to take import restrictions on farm products based on the general safeguard provision under the World Trade Organization if it is proven that imports are surging to an extent that would seriously harm the interests of domestic producers.

The investigation is the first for Japan under the general safeguard provision, though a similar probe has been taken on textile imports under the WTO's textile safeguard provision.

The ministries will try to determine whether the imports actually increased and whether they are causing serious damage to domestic producers, the official said.

The government will make a final decision after a joint team of the three ministries completes hearings from related industries and consumers on April 27.

The agriculture ministry last month requested government investigation of six farm products based on petitions from farmers' groups. The remaining three -- tomatoes, peppers and onions -- were not included as targets of the latest probe, the official said.

Imports of leeks have increased 9.1 fold between fiscal 1997 and 1999, while sales of domestic produce have dropped by 21.1 billion yen from 154.5 billion yen over the same period.

Similarly, it is estimated that the import volume of fresh mushrooms will grow 60 percent between 1997 and 2000 and that the import of rush will increase 140 percent over the same period, MITI said.