TOKYO - Tokyo Steel Manufacturing Co, Japan's biggest maker of construction steel, said it would cut the price of H-shaped steel, its mainstay product, to the lowest level in six years due to weak domestic demand.

It will cut the prices of all products except wire rods in January, which follows an across-the-board price cut in November.

Declines in construction-use steel prices have accelerated as private demand remains weak, while the government has slashed spending on public works, Naoto Ohori, managing director of Tokyo Steel, told a news conference.

We don't know when the market will bottom out.

Tokyo Steel will cut the price of H-shaped steel by 2,000 yen to 63,000 yen per tonne, the lowest since February 2004.

Government incentives for eco-friendly cars have boosted demand for automotive sheet around the world. But Japan's construction market has shown no sign of picking up as companies rein in spending on new plants and consumers delay purchases of new houses amid an uncertain economic outlook.

Shares in Tokyo Steel closed the morning session 2.1 percent higher at 1,057 yen prior to the announcement, outperforming a 0.8 percent decline in the benchmark Nikkei .N225 (Reporting by Yuko Inoue; Editing by Edwina Gibbs)