Amazon.com, which revolutionized reading with its Kindle e-reader, is expected to unveil a tablet computer this week that analysts say will seriously challenge Apple's market dominating iPad.

Amazon on Friday invited media to a press conference to be held in New York on Wednesday, declining to provide further details.

But analysts were confident that the world's largest Internet retailer will introduce its long-awaited tablet computer this year to expand in mobile commerce and sell more digital goods and services.

"Wednesday is tablet day," BGC partners analyst Colin Gillis told Reuters.

The tablet has been awaited as a strong competitor to Apple Inc's iPad. Apple has sold about 29 million of the devices since its launch in April 2010.