Workplace review website Glassdoor will have to reveal the identities of former employees who left negative reviews about New Zealand toy company Zuru.

The company has been wanting to file a defamation suit against the authors of six reviews of the company on Glassdoor but couldn’t because the reviews were submitted anonymously.

To identify the authors, Zuru sought a subpoena from a Californian court which found in Zuru’s favour, ordering Glassdoor to “produce documents that identify who wrote the reviews in question”, as reported by independent journalist David Farrier.

Zuru claimed the negative reviews – which it labelled as “fake and untrue” – forced the company to spend extra money hiring for positions, citing an instance in which it offered a management role to a candidate who turned the job down because of poor Glassdoor reviews.

In his judgement about the subpoena, judge Alex Tse said because Zuru was seeking defamation lawsuits in New Zealand, Glassdoor needed to prove its reviewers’ statements were in line with New Zealand defamation law which contains – in contrast to other jurisdictions – “honest” opinion as a defence.

Tse said the question of whether the reviewers’ opinions were “honest” couldn’t be answered without knowing who they were.

“The reviewers haven’t even been identified, much less appeared in court and offered evidence on the genuineness of their opinions,” he said.

“Zuru, at this point, just wants discovery – to learn who wrote the reviews.”

Glassdoor has now placed a label atop Zuru’s page which tells users the company has taken legal action against Glassdoor and recommends people “exercise [their] best judgement when evaluating this employer”.

A warning now appears at the top of Glassdoor's Zuru reviews page.

A spokesperson for Zuru told Stuff the company was “pleased” the reviews it called “spam” have been removed and that it “cannot comment on anything further relating to pending litigation”.

In a statement, Glassdoor said it was “deeply disappointed” by the court ordering it to hand over identifying information of users.

“We note that, contrary to Zuru’s contentions, the unflattering workplace experience reviews describing working at Zuru were authored by multiple former Zuru employees,” Glassdoor said.

“In this and many other cases worldwide, Glassdoor fights vigorously to protect and defend the rights of our users to share their opinions and speak freely and authentically about their workplace experiences, without fear of intimidation or retaliation.”

Glassdoor relies on the honesty of a userbase that believes they won’t face negative repercussions for speaking out against poor workplaces and claims to have defended against more than 100 instances of employers trying to identify anonymous reviewers.