Social media sites Facebook and Instagram are down for users around the world, with Facebook confirming it is not because of a cyber-attack.

Facebook acknowledged the outage just before 7am NZT, and posted again saying it wasn't because of a denial-of-service attack.

"We're aware that some people are currently having trouble accessing the Facebook family of apps," it says on Twitter.

"We're working to resolve the issue as soon as possible."

People are taking to Twitter to say they are unable to access the websites and apps.

Canterbury Police posted a warning on Twitter asking Kiwis not to call 111 over the issue: "Unfortunately we cannot do anything about this because, you know, they're based in America and we're the Police."

Some users trying to access Facebook were met with a message saying "Facebook will be back soon".

"Facebook is down for required maintenance right now, but you should be able to get back on within a few hours."

New Zealand Parliament also tweeted that the outage would mean its select committee meeting would not be live streamed on Thursday morning.

"Public meetings will be recorded and uploaded to committees' Facebook pages later today," it says.

Instagram has 1 billion active users every month.

As of December 31, Facebook has more than 2.32 billion monthly active users.

Website DownDetector is reporting the issues with the social media sites, focusing on outages reported in the United States and Europe.

On Wednesday, another outage affected Gmail and Google Drive users around the world.

People reported having trouble loading the website and sending emails.

Many vented their frustration on social media.

According to the website outage report, there were 1276 reports of problems with Gmail in a 20 minute period.

They came from the United States, Australia, Singapore, New Zealand, Canada and 55 more countries.

A spokeswoman for Google said it was aware of the problem.

-Stuff.co.nz/Danielle Clent