Worldwide mobile phone market growth is expected to continue in 2005, but at a slower pace, according to a study released Monday by IDC.

IDC, a high-tech market research firm, said it expects mobile phone shipment totals to slow in most regions during 2005 as a direct result of the large number of new phones purchased by wireless subscribers in 2003 and 2004.

In 2004, worldwide mobile phone shipments saw their strongest year-to-year increase in history, rising 34 percent from 2003 to 2004 with 692 million units shipped in a massive expansion driven by the demand for color displays and camera phones.

"The market will continue to expand through 2009, however, offering a significant opportunity for hardware, software, and service vendors alike," said David Linsalata, research analyst, Mobile Devices research at IDC.

The worldwide wireless subscriber base will continue to grow throughout the forecast period, driven by the human desire to communicate, IDC said.

In 2005, the market research firm expects nearly 1.7 billion active wireless subscribers or individuals paying a subscription bill in the world.

Through 2009, wireless subscriber base growth will exist in all regions, although some countries and regions will reach near-full penetration levels by the end of the forecast period, IDC said.