Online whistle-blower WikiLeaks has posted a huge encrypted file named "Insurance" to its website, sparking speculation that those behind the organisation may be prepared to release more classified information if authorities interfere with them.

Bloggers have noted that it's 20 times larger than the batch of 77,000 secret US military documents about Afghanistan that WikiLeaks dumped onto the Web last month.

Contributors to tech sites such as CNet have speculated that the file could be a way of threatening to disclose more information if WikiLeaks' staffers were detained or if the site was attacked, although the organisation itself has kept mum.

"As a matter of policy, we do not discuss security procedures," WikiLeaks said today in an e-mail response to questions about the 1.4 gigabyte file.

Editor-in-chief Julian Assange was a bit more expansive, if equally cryptic, in his response to the same line of questioning in a television interview with independent US news network Democracy Now!

"I think it's better that we don't comment on that," Assange said, according to the network's transcript of the interview. "But, you know, one could imagine in a similar situation that it might be worth ensuring that important parts of history do not disappear."

Assange, a former computer hacker, has expressed concern over his safety in the past, complaining of surveillance and telling interviewers that he's been warned away from visiting the United States.