The 24-hour protest was called in response to compulsory redundancies at BBC Wales.
Four editor posts are planned to be cut, with the dispute revolving around the BBC's failure to reassign the individuals involved.
Production on the likes of Casualty and Welsh soap opera Pobol y Cwm has also been suspended.
Meanwhile, Radio Wales programme Good Morning Wales was replaced by arts programming.
The Doctor Who Christmas special - starring Matt Smith in his second festive episode - will focus on the Time Lord's relationship with Madge Arwell (Claire Skinner) and her two children, Lily and Cyril.
Written by Steven Moffat, the instalment will also star Alexander Armstrong, Bill Bailey and Arabella Weir.
The currently untitled episode will air in late December, with a Christmas Day slot likely but unconfirmed.
> Doctor Who Christmas special filming: In pictures
Watch a prequel for the Doctor Who sixth series finale below: