Staff at some of Greenwich's most iconic historical sites have announced they plan to go on strike for the second time this year.

On New Year's Day, workers at the National Maritime Museum and Royal Observatory Greenwich picketed outside the famous locations.

At the time they announced the strike action was held on that day specifically so it would not impact the public that much, but now further days have been announced.

READ MORE: Staff picket at Maritime Museum and Royal Observatory and warn more strikes may come

The Royal Museums Greenwich (RMG) workers announced they will strike on February 17 due to lack of progress about contractual changes.

Trade Union Prospect said the changes include shorter breaks, unclear shift hours and extra working hours with no extra pay.

Caroline Hemmington, Prospect negotiations officer, said: “This strike is not about stopping people from going to the museum, but to highlight how detrimental these changes have been on the staff affected.

“Members have decided to take a second day of strike action to demonstrate to RMG management how significantly these changes are felt on a day to day basis.

“Prospect is working towards finding a resolution for our members and the best way to do this is by continuing to engage in constructive discussions with management.”

RMG said they felt the new terms of contract meant increased hourly rates of pay and was a benefit to part time staff and those working on overtime.

A spokesperson from Royal Museums Greenwich said: "We very much regret that they feel this is necessary as the new system seems to be bedding in well but at the same time we acknowledge and respect the professionalism shown by all staff as they strive to maintain our service to visitors.

"A reduction of breaks for some of the staff involved has remained at issue and after just over a year of negotiations with the Union, discussions ceased without full agreement being achieved so the decision was taken to impose the new terms and conditions for those staff who had not yet agreed them."