Australian internet provider BigPond has become the latest internet company to be targeted by hackers on Twitter, after one of its accounts was hijacked as part of a phishing scam.

The company, a subsidiary of Sydney-based telecommunications giant Telstra, said that the BigPondTeam Twitter account - which is used to provide information and support to customers - had been infiltrated by unknown criminal and used to trick users into handing over their passwords.

Affected users received a private message from BigPondTeam saying "Hey, look at this," and directing them to follow a link that asked them to enter their Twitter password. The attack was part of an attempt to steal their credentials and potentially gain access to other services they use - such as their bank accounts or email services.

"Someone, identity unknown, used the BigPond Twitter account to send unauthorised direct messages to some of our followers," said a spokesman for Telstra in a statement. "The incident is under investigation with Twitter."

It is not the first time that large telecoms companies have been targeted by hackers on Twitter, as a rising tide of attacks hit the social messaging site.

Earlier this week BT users reported that they had been receiving phishing messages from a Twitter account called BTCare, which is followed by around 3,000 people and provides helpdesk services.

The company denied that its account had been hijacked by criminals, but said that some customers had been targeted.

"The BT Care Twitter account has not been hacked," said a spokeswoman earlier this week. "There is a suspected phishing attack which has affected a small number of our followers."

Spam and phishing attacks have long been problematic for social networking sites, particularly because the messages usually come from people or companies that users trust. Earlier this year Facebook and Twitter issued public warnings to users after a string of attacks, and both services receive a regular stream of reports about similar activities.

Phishing scams are believed to cost internet users billions of pounds each year, but such strikes could be particularly devastating for the reputation of companies that use social media maintain contact with customers without carefully considering the security implications.

Meanwhile, BigPond said that there were important lessons for everyone about security.

"Yesterday reinforces how important it is to stay aware and secure online," said the company.