A massive Sydney power failure has not stopped the city's residents taking to Twitter, with the social-networking site lighting up with a running commentary as people deal with the outage — and the threat of possible undead attacks.

Large parts of Sydney's inner-city areas have lost power, with Energy Australia saying that the fault occurred in two CBD sub-stations at 4:45pm as peak hour hit.

According to the Daily Telegraph, the NSW Fire Brigade has been called out to more than 40 lift rescues and automatic fire alarms.

The emergency has driven many Sydney-siders, such as Alex_Manchester, to use Twitter on their mobile phones as a source of information. "7 minutes battery left. This is going to get ugly", he tweeted.

Some comments have provided useful information, with Twitter user brieucsaffre commenting, "No #blackout in Pyrmont but RT @eunmac People saying the fire is near town hall on Clarence street. Trains still running apparently". (As of 6pm, City Rail's Web site indicated that there were no reported service interruptions.)

The social networking site has also abounded with warnings of an onslaught of zombies in the city's CBD, with Twitter's "trending" topics including #zombies, #blackout and #sydney.

User stephendann reported: "Residents warned of slow moving shambling hordes of hungry zombies leaving Sydney CBD".

Update: According to a spokesperson for Energy Australia all power has been restored as of 6:50pm.