Japanese car giant Toyota on Wednesday slashed its full-year net profit forecast after profits tumbled nearly 30 per cent in the first nine months.

The maker of the Camry sedan and Prius hybrid now expects annual net profit of 1.87 trillion yen ($17 billion) instead of 2.3 trillion yen it projected three months ago.

The new forecast represents a 25-percent plunge from the last year.

Its net profit for the nine months to December came to 1.42 trillion yen, down 29.3 percent from the same period the previous year.

Operating profit rose 9.5 percent to 1.94 trillion yen on sales of 22.5 trillion yen, an increase of 3.1 per cent.

Fellow Japanese automaker Honda last week logged a net-profit fall of 34.5 per cent for the nine months to December but revised up its full-year forecasts thanks to strong motorcycle sales.

Nissan is to announce results next week, the first since its former chief executive Carlos Ghosn was arrested on November 19 for financial misconduct.