Apple is expected to unveil the iPhone SE on Monday, a smaller, more affordable iPhone designed to entice more users to upgrade.
The technology giant had previously forecast a drop in smartphone sales for early 2016, but an alternative to the premium iPhone 6s could draw in more customers.
Speculation suggests the new device could have the same design as the 2012 iPhone 5, but have similar features to the iPhone 6s, which launched in September - including a 12-megapixel camera and the ability to capture 4K video.
The product launch, being hosted at the company's headquarters in Cupertino, California, comes a day before the firm is due in court over its encryption battle with the FBI and the US Justice Department.
Apple could use the event to make further comment on its stance of not helping authorities break into the locked iPhone of a terror suspect by building versions of its software that could help breach its security - a move they argue would compromise user privacy and make their devices more vulnerable to hackers.
Last month, Apple chief Tim Cook called the US government's position an "unprecedented step which threatens the security of our customers".
Some of Apple's rivals in the smartphone market, including Samsung and LG, have already unveiled new phones for 2016 to positive reviews.
The iPhone SE is likely to be regarded as an entry-level device, more affordable than the 6s. It would buck the current trend for smartphones which have been growing in recent years by reverting to a 4in screen not seen on the iPhone since 2014.
The rumoured unveiling could be accompanied by the arrival of a new iPad, with rumours suggesting a smaller and more lightweight iPad Pro, Apple's most recent and largest tablet.