The Department of Commerce, which administers the jobs.nsw.gov.au site, refused to say whether personal details had been stolen from Government servers but the public service jobs site was offline last week for "system maintenance".

It was still not online yesterday and the department would not explain how the incident occurred or when it expected the site to be running.

Catherine Parrott, from Maitland, applied for a Government job earlier this month and soon after received an email from jobs.nsw.gov.au offering her the "perfect job" with large commissions.

The email asked recipients to click on a link or reply for more information but Ms Parrott thought the email was suspicious and deleted it straight away.

Emails offering bogus job vacancies are typically used by spammers to deliver password-stealing viruses or to collect extensive personal details from victims, which can then be used for identity fraud purposes including breaking into internet banking accounts and applying for credit.

Although Ms Parrott did not take the bait, she uploaded her CV to the jobs.nsw.gov.au website when applying for a job and is worried all of her personal details - including employment history, date of birth, address and phone numbers - are now in the wrong hands.

She expected many people would be duped by the spammers because the emails came from a trusted NSW Government email address.

"If someone hacked in, they could use a lot of that information to do dodgy credit and God knows what else," she said.

Steve Turner, the assistant secretary of the Public Service Association of NSW, said the incident was of "serious concern" and the Government had a "responsibility to protect everyone's data" by maintaining secure computer systems.

"What the PSA would be concerned about is who is actually managing the system, protecting and repairing it. If that's been [outsourced], that raises serious concerns as well about the appropriate response and protection by the external provider," he said.

Mr Turner said the blame did not lie solely with the Government as "any computer system can be hacked … even American defence force computers".

As if to illustrate his point, New Zealand media reported that a New Zealand tourist had found confidential United States military files on an MP3 he bought at an op shop in the US.

A Department of Commerce spokeswoman said the Government was aware that users of jobs.nsw.gov.au "received spam emails advertising a non-existent job vacancy". She advised people who received the suspicious emails not to reply and to delete them immediately.