Apple and Samsung are believed to be planning the release of 12-inch tablets, according to a report by Taiwan’s DigiTimes.

Apple is thought to be cooperating with Quanta Computer on its device, while Samsung is developing the product in-house.

DigiTimes further reports that Samsung originally hoped to partner with Google for its 12-inch tablet, but went cold on the idea when the search-engine giant switched most of its tablet attention to 7-inch products.

Samsung is the manufacturer of Google’s Nexus 10 tablet.

The paper’s sources, described as coming from the “upstream supply chain”, admitted there are worries about large-size tablets affecting notebook demand.

Both Apple and Samsung already offer tablets in several sizes, although neither has gone above 10-inches before.

The Register said that a KGI Securities analyst had argued that Apple would not launch a bigger device, because it “would not provide a good mobility experience given today’s technology limitations”.

(The DigiTimes sources also say that Quanta has become a supplier of Apple’s long-rumoured, but so-far unannounced, iWatch.)