Nippon Telegraph and Telephone Corp. plans to invest 1.52 trillion yen on plants and equipment in fiscal 1999, down 230 billion yen from the current business year, the carrier announced Friday.

Of the planned investment, the country's largest telecom carrier plans to invest about 1.1 trillion yen on networks and other facilities for voice transmission services. The proposed amount is a decline of 170 billion yen from the current business year, which ends March 31.

NTT expects the number of ordinary telephone subscribers to further decrease to 56.2 million by the end of March 2000, following a drop to 58.5 million by the end of next month. NTT submitted the business plan to the minister of posts and telecommunications for approval on Friday. The central government is the biggest shareholder of the former state-run carrier, currently owning about 940,000 shares of NTT's 1.6 million shares.

Meanwhile, NTT estimates 216 billion yen in pretax profit for the business year that ends March 2000, down 26.3 percent from the current business year. The carrier estimates 6.1 trillion yen in sales for the same period.

NTT expects that revenue from voice transmission services will decline 4.9 percent to 4.4 trillion yen due to such reasons as the increase in mobile telephone users, the stagnant economy and intensifying competition.

In contrast, the carrier expects that revenue from data transmission services will grow 43.1 percent to 166 billion yen.