The new Clié will be Sony's first in Japan since it launched the PEG-T400 and colour-screen equipped PEG-T600 in November last year.
Sony's announcement will come as Palm Computing KK, the Japanese unit of Palm, cuts the number of products available in Japan.
Palm is discontinuing its M100 and M105 models after a three-month promotion that saw the M100's price slashed to ¥4,900 (£26) and has no plans to sell the new M130 in Japan, said Maki Hashizawa, a spokeswoman for Palm.
There are also no plans to sell the wireless-enabled i705, also announced last week, said Hashizawa, adding Palm plans at present to continue selling only the 500 and 505 models in the Japan market.
Palm's promotional prices and its decision to cut the range of PDAs offered in Japan comes in the face of fierce competition from many of Japan's largest electronics companies. Sharp had led the market with its Zaurus range of PDAs for some time and the entrance of Palm and Handspring provided the first sparks of competition.
When Sony backed Palm, things were looking good for the platform, but in the last year Microsoft's Pocket PC system has risen in significance after a number of companies entered the business with devices based on Pocket PC. Casio Computer, NEC, Toshiba, Fujitsu have launched Pocket PC-based devices, and Hitachi has just entered this market.
The most recent promotion by Palm was a success, said Hashizawa. While the company would not release sales figures, the spokeswoman said sales were three times higher during the promotional period than in the three preceding months. "The market reaction was very positive," she said. "We have had lots of sales."