Apple has moved ahead the production for its planned new 10.5-inch iPad to March instead of an earlier timetable set for May-June and is expected to unveil the new iPad at a product event to be held in early April to mark the inauguration of Apple's new headquarters in California, according to Taiwan-based supply chain makers.

The 10.5-inch iPad will target education and business sectors, and together with an upgrade 12.9-inch iPad Pro, the two models will be Apple's mainstream products for the mid-tier to high-end tablet market in 2017, said the sources.

Since sales of tablet products have been flat recently, initial shipments of the 10.5-inch iPad are likely to reach only one million units in March, and are expected to ramp up to 1.2 million units a month from the second quarter, the sources noted.

Meanwhile, Apple's orders for an upgrade 9.7-inch iPad have been steady since February, with shipment volumes likely to reach 3-4 million units a month in the first quarter and grow significantly starting the second quarter, the sources noted.

However, the production schedule for an upgrade 12.9-inch iPad Pro still remains unclear. The sources estimated that volume production of the new 12.9-inch iPad Pro may kick off in May-June.