The data was stolen last month by hackers that threatened to publish it unless the match making site for married people was taken down.
Some data was released in July but Avid Life Media, which owns Ashley Madison, has confirmed that more data has now been leaked.
The Canada-based company said it had "now learned that the individual or individuals responsible for this attack claim to have released more of the stolen data".
It added: "The criminal, or criminals, involved in this act have appointed themselves as the moral judge, juror, and executioner, seeing fit to impose a personal notion of virtue on all of society. We will not sit idly by and allow these thieves to force their personal ideology on citizens around the world."
The group behind the hack refer to themselves as "The Impact Team".
"Avid Life Media has failed to take down Ashley Madison and Established Men," Wired quoted Impact Team as saying in a statement accompanying the latest posting.
"We have explained the fraud, deceit, and stupidity of ALM [Avid Life Media] and their members. Now everyone gets to see their data," the hackers said, according to Wired.
Shortly after the breach, a hacking insider told Sky News that hackers could sell the data they hold on Ashley Madison's 37 million cheating users for a large profit.
Initially the hackers released just 40MB of data, including some credit card details and several documents about its parent company Avid Life Media (ALM).
The hackers said they were prepared to release all customer records, including the "secret sexual fantasies" of members, unless the site was closed.
Ashley Madison, whose tagline is "Life is Short. Have an Affair", is founded on confidentiality and privacy. It facilitates relationships between married people looking to cheat on their spouse.
The Impact Team targeted ALM over its Full Delete feature - a £15 ($19) service that allows Ashley Madison users to remove their profile and all accompanying information. The hackers claim that ALM doesn't actually delete everything, stating that the user's real name and credit card details remain online.
In April, ALM claimed Ashley Madison was the second most popular dating site in the world, losing out only to dating giant Match.com. It also claimed Ashley Madison had 1.2 million users in Britain.
Commenting at the time of the hack, Kassem Younis, a privacy expert and CEO of Thoughts Around Me, an app that lets people share things anonymously about issues affecting their everyday lives, said Ashley Madison has let its users down by failing to protect them.
"There are many reasons why people would want to protect their identities online - whether or not you agree with the premise of this particular service, users have placed their trust in Ashley Madison and have been badly let down. What is most worrying is that this points to a wider trend of anonymous apps and websites being hacked, including Secret in August 2014.
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