Amazon.com Inc (AMZN.O) said it will hire more than 2,000 seasonal workers in Canada and 120,000 in the U.S. for the holiday season, highlighting the growing threat the e-commerce giant poses to traditional retailers.

The U.S. hiring plans marks a 20 per cent increase from last year. Amazon will also hire hundreds more ongoing full-time roles for its facilities in the Toronto and Vancouver areas, a spokesperson for the company said.

U.S. retailers such as Macy's Inc, Target Corp  and Kohl's Corp have said they plan to hire fewer temporary workers or to keep seasonal employment levels little changed this holiday season.

More than 14,000 seasonal positions were transitioned to regular, full-time roles after the holidays last year, and the company expects to increase that number this year, Amazon said on Thursday.

The U.S. National Retail Federation earlier this month forecast a 3.6 per cent rise in holiday sales this year, with online sales expected to climb 7 per cent to 10 per cent.

Brick-and-mortar retailers' biggest challenge in recent years has been tackling the growth of online retailers, specially Amazon, which offer the same products at lower prices and have made shopping more convenient.

They are also keeping sales expectations and inventories low - and hiring light - ahead of the holiday season to avoid a repeat of last year, when unusually warm weather hit sales and piled up unsold goods.      

With files from BNN