MADRID, Nov 20 (Reuters) - Spanish union CCOO on Monday called on 20,000 warehouse and delivery workers at Amazon's (AMZN.O) local unit to stage a one-hour strike on each shift on Nov. 27, a date known by retailers as 'Cyber Monday', and the same on the following day to demand better wages and working conditions.

There are three working shifts a day at Amazon in Spain.

"It is symbolic, but it is a first move and we will consider other kind of actions in the future," the union's secretary general for Amazon, Douglas Harper, told Reuters.

CCOO, the largest union at the U.S. retailer in Spain, wants the company to improve labour safety and acknowledge workplace risks in Spain, boost human resources staff and raise wages, arguing that the pay does not reflect the volume of workload.

"Our staff in all of Spain already work in a safe and modern environment with competitive wages and benefits," a local Amazon spokesperson said in a statement sent to Reuters.

Cyber Monday is the first working day after Thanksgiving, an important date for retailers as consumers return to work and start ordering Christmas gifts.

Even though the date is not that significant in European countries as they do not celebrate Thanksgiving, online retailers also offer discounts and launch special offers similar to those in the United States.

Logistics workers at Amazon on both sides of the Atlantic have complained about working conditions and unionisation is starting to build pressure on the company. A group of workers walked out in Britain earlier this month despite a pay raise in October.

Amazon has grown fast Spain in the past couple of years in both logistics for its e-commerce business and data centres to support its cloud computer unit, Amazon Web Services.