Cyber-hackers broke into South Africa's official statistics website on Monday, replacing details of the latest consumer price index with a slew of obscenities railing against national phone company Telkom.

Visitors to the site (www.statssa.gov.za), which normally provides information on staid topics such as manufacturing production and gross domestic product growth, were met instead with a foulmouthed tirade against Telkom's alleged shortcomings.

"Telkom stop your...lame-ass monopoly or we will disconnect you," the hackers warned, among other things.

The page is a crucial source of information for economists tracking the country's performance.

Many of Telkom's unionised workers are involved in a wage dispute with the employer and have engaged in organised go-slows. But a Telkom official said she didn't believe the defacing of the statistics website was related.

Telkom's site (www.telkom.co.za) wasn't affected.

An information technology expert at Statistics South Africa said it could take at least two days to get the site back to normal.