Dragons director of rugby Dean Ryan hopes the "integrity of derby games will remain" as league organisers face the challenge of rescheduling.

Ryan says it is "incredibly disappointing" as those fixtures are the "heart of the season".

He hopes they will be rescheduled outside the Six Nations window.

Scarlets are due to host Ospreys behind closed doors on Saturday, 1 January in Welsh rugby's remaining festive derby with Dragons at Scarlets also due to be played seven days later.

URC bosses have already said that round six and seven fixtures due to be played in South Africa involving Scarlets, Cardiff, Munster and Zebre will take place on the final two weekends of the Six Nations in March.

Schedulers now have to turn their attention to the games called off in December and the start of January - so far there are eight involving Welsh, Irish and Scottish teams.

"I recognise that there is other people going to be in charge of that, and I also recognise that it's going to be an incredibly complex job," Ryan told BBC Sport Wales.

"There are available weekends outside the Six Nations, we're all aware that we're running out of them, but if there is a weighting applied I hope that weighting would go against the derbies... we all know how important they are.

"They're everything that Welsh rugby is great about.

"Everybody from Wayne Pivac to every supporter wants to see them [international players] going at each other because it makes selection a lot easier and form a lot easier to see."

Ryan confirmed that Dragons currently have 17 positive Covid cases, but they are preparing to take on Scarlets as planned on Saturday, 8 January.

"It is difficult because we're avoiding certain types of training just until we get aware of how it's multiplying within the squad," he said.

"We hope by next Tuesday we get a clearer picture from all four sides over whether we can progress with a normal training week and hopefully get back to playing."

Asked if he thought the league would benefit from a pause in play or a "firebreak", Ryan said: "I would have said our thoughts last week would have been around that because everyone was aware of how these cases were springboarding.

"But also I recognise that URC have got a huge fixture challenge. Obviously losing the games in South Africa, the derbies across all nations were seen as the stable part of the season.

"We're going into Europe very soon and that's got its own challenges and we've the Six Nations on the horizon so it's not a huge amount of time.

"We've got to get these players back playing.

"But at the moment's it's about health, let's get our squads healthy again, let's hope the nation is moving towards a more positive outlook and we'll see where things move next week."