Royal Mail workers have announced that they will be adding six more strike dates before the end of the year, including one on Christmas Eve.

The Communication Workers Union (CWU) stated that its members would walk out on December 9, 11, 14, 15, 23 and 24.

These strikes come at key dates before Christmas and will undoubtedly cause huge problems in the delivery of parcels and letters in what is the busiest time of year for the service.

A CWU spokesperson said: “The CWU want a negotiated settlement with Royal Mail Group and will continue to engage the company to that end.

Impartial Reporter: Royal Mail says that contingency plans are in place for the strikes Royal Mail says that contingency plans are in place for the strikes (Image: PA)

“But those in charge of Royal Mail need to wake up and realise we won’t allow them to destroy the livelihoods of postal workers.”

A Royal Mail spokesperson said: “Our preference is for an agreement with the CWU but the change we need is not optional.

“They should be focused on a resolution to this dispute for their members and the long-term health of the business, rather than damaging strike action.”

The long-running dispute between the CWU and Royal Mail relates to pay, jobs and working conditions.

READ MORE: Royal Mail stamps without barcode will be unusable within 100 days

Royal Mail workers have already walked out several times this year, such as in August and September, and strikes are already set to go ahead for November 24, 25, 30 and December 1.

As reported by LadBible, the Royal Mail explained in a message to customers on its website that it had 'well-developed contingency plans', but warned it 'cannot fully replace the daily efforts' of its frontline workforce.

"We’ll be doing what we can to keep services running, but we are sorry this planned strike action is likely to cause you some disruption," it added.