The new iPads were unveiled on the same day Microsoft began selling an upgraded version of its Surface tablet, and as Nokia unveiled its own tablet computer.
Industry tracker Gartner on Monday forecast that global tablet shipments will reach 184 million units this year — a 53.4 percent rise from last year.
The iPad remains the largest-selling tablet, according to surveys, but its market share is being weakened by rivals using the Google Android operating system.
Apple is also under pressure to adapt to the popularity of premium tablets with high-quality screens in the seven-inch to eight-inch range where the Mini competes.
Jan Dawson, analyst at the research firm Ovum, said Apple’s latest innovations should “trigger good upgrade sales and get iPad shipments growing again.”
However, Apple is also raising the price for the new Mini, unlike competitors, which Dawson said means Apple’s share in tablets will continue to fall as Android’s share rises over the coming years.
Apple shares fell 1.5 percent to end at US$519.87, but were regaining lost ground in after-market trades.