WikiLeaks has published what purports to contain "new" Democratic Party documents hacked by the Guccifer 2.0 hacker.

Republican presidential candidate Donald Trump. AP

The organisation posted a tweet at around 9am on Wednesday Sydney time, with links that promised access to 678.4 megabytes of new "DNC documents".

Initial images of what appeared to be presentation slides show information about databases used for voter identification and turnout efforts.

Julian Assange on the balcony of the Ecuadorian embassy. Getty Images

Other slides discuss the outcome of past get-out-the-vote campaigns.

Democratic presidential candidate Hillary Clinton was US secretary of state when WikiLeaks released hundreds of thousands of State Department emails in 2010.

The latest document dump comes after an earlier tranche of emails, reportedly hacked by Guccifer 2.0, prompted the resignation of politicians within the Democratic Party on the eve of the party's convention.

WikiLeaks, in the guise of transparency, has emerged as a key antagonist in the US election, publishing information mixed with speculation and conspiracy theory material on social media, aimed at embarrassing Democratic presidential candidate Hillary Clinton.

Democratic presidential candidate Hillary Clinton . AP

In the earlier event, the data is thought to have been acquired by hackers associated with Russia.

WikiLeaks, too, has been suspected of working to advance Russian talking points in recent years.

WikiLeaks Supplied

US officials are now investigating whether Russia is pursuing a campaign to influence the outcome of the US presidential election between Ms Clinton and Republican candidate Donald Trump.

US-based intelligence expert Malcolm Nance said WikiLeaks is acting as a conduit for Guccifer 2.0 which, he says, is a joint operation for Russian intelligence groups, the FSB and the GRU.

Nance said Assange has a long history of dislike for Clinton.

"He's in FSB hands and he doesn't care," Nance said.

WikiLeaks denied the claims that the organisation was being manipulated by a nation state.

"The accusations are false and defamatory," a spokesman for WikiLeaks said.

"The motivation for them is transparent: our pending publications on Hillary Clinton's campaign."

WikiLeaks also defended the quality of the information it disclosed.

"WikiLeaks has a perfect record for verification," the organisation told Fairfax Media.

In response to the latest data exposure via WikiLeaks, interim chairwoman of the DNC Donna Brazile said the Democratic Party was "the victim of a crime - an illegal cyber attack by Russian state-sponsored agents who seek to harm the Democratic Party and progressive groups in an effort to influence the presidential election."

"There's only one person who stands to benefit from these criminal acts, and that's Donald Trump," she said, pointing to his rhetorical "embrace" of Russian president Vladimir Putin.

Trump often spoken highly of the Russian president. The Republican's public admiration of the Russian leader has caused consternation across the political spectrum in the US.

The DNC's legal team was reviewing the "private documents" and attempting to confirm their authenticity, "as it is common for Russian hackers to forge documents."

Brazile took over as the DNC chairwoman in July after Debbie Wasserman Schultz resigned in the wake of an earlier Guccifer 2.0 data release.

Brazile added that "We would urge anyone attempting to access these documents to proceed with extreme caution given the potential malware risks."

Australia-based information security researcher Lee Johnstone also expressed concern about the possibility of malware on hacked and leaked documents.

"Checking documents and leaks like this should always be conducted in a safe environment on a decentralised virtual machine," he said.