Nicola Roberts says she refused the government’s request to endorse its Online Safety Bill, due to “loopholes” in the legislation.
The singer said was asked to “champion” the bill after suffering abuse, harassment and online stalking.
But she said the draft bill does not do enough to stop people who’ve been banned from setting up new accounts.
The government said the legislation would tackle anonymous accounts without imposing a “blanket ban” on anonymity.
“I am unconcerned with chasing the rabbit,” she said in a statement. “I would rather just fill the hole.”
Roberts said she had been invited to discuss the bill by the Department for Digital, Culture, Media and Sport (DCMS) two weeks ago.
Although the meeting was private, she said the racist abuse aimed at Marcus Rashford, Jadon Sancho and Bukayo Saka after Sunday’s Euro 2020 final on Sunday strengthened her conviction that the legislation needed to be tougher.
“The online racism we have seen since last night’s England game targeted at, in particular, a 19-year-old is despicable,” she said.
“Regardless of whether an abuser’s account is blocked or taken down, perpetrators make the time to start another and start again. It highlights why those loopholes need to be filled and this has to stop!”
In response, a DCMS spokesperson said anonymous accounts were important for certain groups of people, including those “exploring their sexuality or suffering domestic abuse”.
However, they added, the proposed bill would force social media companies to meet a duty of care, “which will mean stopping repeat offenders from opening new accounts and working with the authorities to make it easier to find people who set up accounts anonymously to abuse others”.
Roberts said she was asked to lend her support, alongside other public figures, in the hope of the bill becoming law.
However, after reading the draft legislation, she explained she “couldn’t support the bill until something more concrete was developed”.
“It would be unproductive and a slap in the face for me to support something that ultimately was still contributing to countless people experiencing abuse online,” she added.
The singer, who won the first series of The Masked Singer last year, urged fans to write to their MPs demanding a tougher solution.
“It’s not the overall fix in combating why people are hateful,” she said. “But it’s a piece of the puzzle that helps keep people safer online.”