Government employees in Ontario can no longer access Facebook, the popular social networking website, on their computers.

To the chagrin of some of the thousands of workers -- including Liberal aides, backbenchers and cabinet ministers -- the 21-million member site is now blocked by the provincial ban.

As of Tuesday, when workers tried to access the site, they were greeted with the same "access denied" message that pops up if someone tries to access a pornography site, according to the Toronto Star.

Facebook is the latest website to be banned by the province, joining YouTube, online poker gambling websites and hardcore sex sites, Government Services Minister Gerry Phillips told the Star.

"The staff determined it's not as directly related to the workplace as we'd like it to be so we're restricting access to it," he said.

"Our IT (information technology) people are pretty broadly familiar with the marketplace and they said, `Here's a website that's going to be increasingly more popular for the OPS (Ontario public service). Is this an appropriate website to be spending time on?'"

"It's the ministry making these decisions on trying to ... restrict access to ones that are inappropriate and then to anticipate where one may grow in popularity and we may end up with a lot of OPS time being taken (up) on it."

Despite the crackdown, rival MySpace is still accessible by provincial employees.

Premier Dalton McGuinty weighed in on the ban, saying he doesn't see how Facebook adds value to a workplace environment.

He says it's important for the government to review websites that are accessible through its computers from time to time.

Facebook chief privacy officer Chris Kelly told the Star that his company was "concerned" about the decision and that they had made "preliminary contact" with Ontario officials.

 David Zweig, associate professor of organizational behaviour at University of Toronto, says employers need to be careful of the message they send when they ban websites at work.

"It's the organizations' right to determine what communication tools are and are not appropriate in the organization. But it is really important to communicate that very early to employees," Zweig told CTV Newsnet.

"So, for example, having employees show up at their terminals in the morning and find out that they can't access a website with no justification sends a strong message that the employer doesn't really trust them and they may perceive that as unfair."

Canada is the fastest growing market for the Facebook website with more than two million users. In Toronto, there are more than 500,000 registered users.

Those who register on Facebook essentially create their own personalized website, complete with a list of their friends, photo albums, and a message board they can choose to make public.

There are also networks you can join that extend your friend base -- anything from your place of employment, the city you live in, or the high school you went to.