Elon Musk’s decision to grant amnesty to accounts previously banned from Twitter amounts to “opening the gates of hell to some of the worst people on the internet”, one expert has said.

Social media commentator Matt Navarra said the decision was “bonkers” and would allow banned users to “come back from their Twitter jail cell” to “harass, abuse and disrupt” others on the site.

Mr Musk’s announcement came after he asked in a poll posted to his timeline to vote on reinstatements for accounts that have not “broken the law or engaged in egregious spam” – the yes vote was 72%.

“The people have spoken. Amnesty begins next week. Vox Populi, Vox Dei,” Mr Musk tweeted using a Latin phrase meaning “the voice of the people, the voice of God”.

Last week, the billionaire restored Donald Trump’s account after a similar poll – although the former US president has not yet tweeted again – and since taking over Twitter he has also allowed Ye, formerly known as Kanye West, to return after he was suspended for antisemitic comments.

The new amnesty – which Mr Musk has said will begin next week – could see a number of far-right and controversial figures allowed back on the platform, including Katie Hopkins and former Trump advisor Steve Bannon.

He has not yet offered any further details on how Twitter would decide which banned accounts would be considered for a return.

Mr Navarra also warned there appeared to be no new technology or policies in place to help Twitter manage the return of figures who had previously used the site to spread abuse, hate, and division.

“It’s very hard to see any benefit or logical reason why this decision has been made,” he told the PA news agency.

“There doesn’t seem to be any new technology or policies in place to counteract the risk that bringing these people back on the platform will bring.

“Twitter already doesn’t have the greatest track record in content moderation and managing this sort of abusive, harassing behaviour – and that’s with these people locked down – so for them to come back, I struggle to see how it could be anything but bad news.”

The Tesla and SpaceX CEO has repeatedly spoken of his belief in allowing more free speech on the platform and in reversing permanent bans from Twitter, despite warnings from online safety groups that it would spark a rise in abuse and harm on the site – researchers have already reported sharp rises in abusive content appearing on Twitter since Musk completed his takeover.

Mr Navarra said he understood Mr Musk’s proposed amnesty “from a free speech point of view” in allowing previously banned users to “at least have a baseline presence” on the site and moderating their reach as needed but predicted a number of issues would arise from the decision.

“I think that makes sense but there still doesn’t seem to be the technology in place to handle it and he certainly doesn’t have the staffing levels required to handle the potential meteoric rise in abuse that we’re likely to see from such a decision,” he said.

“I think it’s bad news for most people on the platform – even those who have never experienced harassment and abuse before. There’s nothing positive that can come of this.

“The only people that this move satisfies are those that are guilty of some of Twitter’s worst crimes.”

He added the decision could be “another nail in the coffin” for Twitter’s advertising business, with some advertisers having already paused work with the platform over concerns about Mr Musk’s new approach to content and moderation.