Viewers said their screens were showing a still from a programme for about 25 minutes before returning to normal. Moments later, the channel was said to have frozen again.
More 4 was showing flashing images on its screen, according to other viewers.
Some said Film4 and E4 were also affected.
It is unclear what caused the issue or how long it will last.
The broadcaster confirmed two channels were temporarily off air in a tweet but did not mention the others.
It said: “Channel 4 and More 4 are currently off air due to a technical problem. We are working to restore them as quickly as possible.”
Channel 4 and More 4 are currently off air due to a technical problem. We are working to restore them as quickly as possible
— Channel 4 (@Channel4) September 25, 2021
S4C, the Welsh language public service TV broadcaster, also tweeted it was facing issues due to a fire at a distribution centre in London.
It said: “Unfortunately following a fire at a London distribution centre we are experiencing technical problems. Apologies.”
Separately, Channel 5 was also said to be faced with technical issues and went off air on Saturday.
Some viewers said they were only shown a message on the channel which said: “We apologise for the interruption. We’ll be back with you as soon as we can.”
A Channel 4 spokesperson said: “We did come off air due to technical issues and steps were taken to put this right as soon as possible.”
Channel 5 have been contacted for comment.