In her first public address since she leaked a trove of damaging documents about Facebook's inner workings, whistleblower Frances Haugen urged her former boss, Mark Zuckerberg, to step down and allow change rather than devoting resources to a rebrand.

"I think it is unlikely the company will change if [Mark Zuckerberg] remains the CEO," Haugen told a packed arena on Monday at the opening night of the Web Summit, a tech fest drawing dozens of thousands to the Portuguese capital, Lisbon.

The former Facebook product manager replied in the positive to the question of whether Zuckerberg should resign, and added: "Maybe it's a chance for someone else to take the reins...Facebook would be stronger with someone who was willing to focus on safety."

The social network, with nearly 3 billion users, changed its name to Meta last week, in a rebrand that focuses on building the "metaverse," a shared virtual environment that it bets will be the successor to the mobile internet.

But early adopters of the virtual worlds known as the metaverse blasted Facebook's rebranding as an attempt to capitalise on growing buzz over a concept it did not create to deflect from recent negative attention.

Commenting on the rebranding, Haugen said it made no sense given the security issues that have yet to be tackled.

"Over and over Facebook chooses expansion and new areas instead of sticking the landing on what they've already done," Haugen told an animated crowd which frequently burst into applause as she spoke.

Facebook's announcement came amid strong criticism from lawmakers and regulators over the corporation's business practices - particularly its enormous market power, algorithmic decisions and the policing of abuses on its services.

The social media network, which operates a dual class share structure through which Zuckerberg and a small group of investors control the company, has hit back saying the documents leaked by Haugen were being used to paint a "false picture."

Haugen told British and American lawmakers last month that Facebook would fuel more violent unrest worldwide unless it curbed its algorithms which push extreme, divisive content and prey on vulnerable demographics to keep them scrolling.

"A key problem is that the foundation of the platform's security is based on monitoring content language by language, which does not scale to all the countries where Facebook operates," Haugen noted.