Japan will provide 4 million US dollars to help build an early warning system for tsunamis in the Indian Ocean, Chief Cabinet Secretary Hiroyuki Hosoda said Wednesday.

The UN International Strategy for Disaster Reduction has proposed building such a system for 8 million dollars, but has also suggested the cost could grow to 20 million dollars.

The aid for the system will come from the 250 million-dollar grants Japan has offered to provide through international organizations, Hosoda said. It has pledged another 250 million US dollars as bilateral grants-in-aid.

Japanese Prime Minister Junichiro Koizumi will announce the specific aid during a UN disaster reduction conference to be held Jan. 18-22 in Kobe, where a special session on the proposed tsunami warning system is planned, he said.