Canadian smartphone maker BlackBerry is wooing Apple customers with a cash offer for trade-ins of iPhones for its new square-screened, keyboard-equipped Passport.

The promotion was announced late on Monday and will be available starting next month until February 13, in Canada and the United States.

Customers who trade in their iPhones could receive up to $US400 cash back depending on the model and condition of their trade-in, plus a $US150 gift card.

This marks the first time that BlackBerry has gone head-to-head with Apple since the Canadian firm launched a turnaround plan last year aimed at stemming massive losses.

The Passport was launched in September.

Named for its approximate size to the travel document, the phone was designed to win back key corporate users after BlackBerry was effectively knocked out of the highly competitive consumer smartphone market dominated by Apple and Samsung.

Investors seemed pleased, pushing up the Ontario-based company's share price slightly in morning trading.

But analysts were more sceptical.

Carl Simard of Medici called it a "desperate move".

In September, BlackBerry reported it narrowed its loss in the latest quarter, and expressed optimism that its major restructuring and new business-friendly devices would help fuel a turnaround.

For the three months ended August 30, BlackBerry posted a loss of $US207 million on $US916 billion in revenues, largely split between sales of services and software and more than two million smartphones.