Smartphone shipments are likely to surpass the 1 billion mark in 2016 as new products are released, according to a new study.

NPD DisplaySearch predicts that smartphone shipments, including new and replacement phones, will total about 567 million in 2012. This is up from just over 250 million two years ago.

However, NPD DisplaySearch downgraded this year's forecast for new phone purchases from roughly 220 million to 177 million, the company said Wednesday. The volume of replacement phones is expected to increase as new smartphones enter the market.

The market research and consulting firm predicted that new smartphone purchases will decline in 2013 and then remain mostly steady until 2016 when a dip is expected, according to NPD DisplaySearch's report, Smartphones: Displays, Designs and Functionality. That decline is expected to be offset by increases in replacement phones being shipped.

Apple's (AAPL) iPhone 5, which was scheduled to be announced Wednesday, will be a "key product for the smartphone market in the second half of 2012," Hiroshi Hayase, vice president of small/medium displays for NPD DisplaySearch, said in a news release. "Apple shipped more than 140 million phones in 2010 and 2011, so we can expect smartphone shipments to continue flourishing as users upgrade to the new iPhone."

NPD DisplaySearch is a unit of NPD Group, a provider of consumer and retail market research based in Port Washington, N.Y.