Foxtel's online streaming services have crashed on the same day the seventh season of Game of Thrones was released on the platform.

In angry social media posts, fans of the HBO television show said they had tuned in to watch the new series, but were met with an error message.

Foxtel confirmed its services — including Foxtel Now, Play and the Foxtel App — were down.

"We are devastated that due to unprecedented demand, we are experiencing problems with our online services this evening," Foxtel said in a statement posted on Facebook.

"Obviously this comes at a time when so many of our customers are wanting to watch the first episode of season seven of Game of Thrones."

Foxtel said it was "doing everything we can" to resolve the problem, and told fans they could watch the episode later using its "On Demand features".

With the show a popular target for illegal downloads, Foxtel screened the new episode at 11:00am (AEST) — the same time as its release in the United States — and again at 8:30pm (AEST).

Some users said they were frustrated they had "tried to do the right thing" by paying for the streaming service, rather than downloading pirated versions.

"At this point it's just easier to torrent Game of Thrones than do the right thing and get Foxtel to work … just a joke," Luke Johnson posted on Twitter.

Fellow Twitter user Lauren said she had subscribed to a Foxtel service to avoid illegally downloading the show.

"And it isn't working!! This is why people pirate!" she wrote.