At least 700 Australian government and police employees outed as users of Ashley Madison website

Up to 700 Australian government and police workers have been revealed as account holders on the Ashley Madison dating web service, following a leak by hacking group Impact Team.

The hack, which follows a threat made by the group in July, exposed the personal information of hundreds of the site’s users in a data cache dump of the Ashley Madison website to the dark web on Wednesday.

Employees of the federal departments of health, education and environment, the ABC, the NSW Attorney-General's Department, and departments of defence and foreign affairs have been implicated as users of the website which bears the slogan, “Life is short – have an affair”.

Dozens of accounts also reveal email addresses purportedly associated with police officers from NSW, Victoria, Western Australia, South Australia and Queensland, including a senior officer.

Websites such as Trustify and ashley.cynic.al are currently offering the ability to search the full database by email address, although user security is not guaranteed when using such unverified services.

The leaked data, which totals almost 10 gigabytes in size, includes credit card details, email accounts and home addresses.

Experts have warned the hacking scandal could expose government employees as well as private individuals to blackmail and extortion.

A large percentage of users have been identified as Australian, with four Aussie cities appearing in one ranking of the world’s top 25 cities according to concentration of Ashley Madison users.

With the data suggesting there are more than 250,000 users in Sydney alone, Australia’s most populous city comes in at number three.

"Avid Life Media has failed to take down Ashley Madison and Established Men," the hacker group posted on a website on Wednesday.

Avid Life Media, a Canadian-based company, owns both websites.

"We have explained the fraud, deceit and stupidity of ALM and their members," the hacker group continued.

"Now everyone gets to see their data."

The hackers responded to the data dump by saying it had referred the matter to law enforcement agencies.

"This event is not an act of hacktivism, it is an act of criminality," the company said in a statement.

"It is an illegal action against the individual members of AshleyMadison.com, as well as any freethinking people who choose to engage in fully lawful online activities."

Last year Ashley Madison claimed to have more than 17 million users in 26 countries.