Nine office workers employed by a Labour-run local authority have lost their jobs after it was discovered that they were spending up to two hours a day on the internet auction site eBay.

Three were sacked and six resigned when they were confronted with the records of their online dealings by managers at Neath Port Talbot Council in South Wales.

The six women and three men, who were earning up to £25,000 a year, were the worst offenders when IT experts investigated the amount of time that staff were spending on eBay.

After the dismissals union officials said that the employer had “put temptation in their way” by allowing computer access to external internet sites. They called on all large employers to install a firewall program to prevent staff from being distracted by sites such as eBay, BBC Online and those that provide gambling.

Hywel Jenkins, the head of financial services at the council, which employs 7,500 people, said: “The main reason for carrying out the investigations was the significant time officers were spending on the internet.

“This highlighted an unacceptable level of usage of shopping, entertainment and BBC/Sky-related websites.”

The council has security software to prevent staff getting access to pornography or other inappropriate websites, but not eBay.

Graham Jones, the head of strategic personnel at the council, said: “We have a policy of allowing employees to use the internet in their own time. We know it benefits them as well as the council as they became more expert in using it and more IT-aware.

“But we clearly don’t want them to use it in council time — at the end of the day they are employed to do a job of work, not be shopping online.”

Mark Fisher, a welfare officer with the union Unison, said that some office workers become “addicted” to certain websites.

He said: “People get very involved in eBay, Sky Sports and their favourite soccer teams. It happens in many, many offices. Obviously we cannot justify people spending a couple of hours of working time looking at these sites, but temptation was put in their way.

“We plan to push for the authority to make changes to its IT system to help to prevent workers landing themselves in hot water. We want firewalls installed to prevent staff accessing these sorts of websites at any time other than between the traditional lunch breaks between noon and 2pm.

“We are looking at how the system can be tightened up so these people won’t get dismissed. These were decent, well-paid jobs in admin, earning between £20,000 and £25,000 a year.”

Unison is now considering whether to support the sacked workers, who are aged between 21 and 44, if they decide to take action for unfair dismissal.

Paul Elliot, the head of local government for Unison Wales, said: “We are examining the case of those dismissed to see whether there are grounds to take matters to an employment tribunal. We have asked the council to adjust their IT equipment to block off certain functions such as eBay sites during working hours. The council could have brought in mechanisms to prevent workers going into the sites. Now we are asking them to put in a system to prevent people from falling into the trap of shopping on eBay.”