Products that could cause electric shock or fires remain for sale on Wish.com despite being highlighted in a BBC Watchdog investigation.
Hair clippers and a hair dryer were among items flagged on Wednesday. They are still available on Wish's site.
The US company's failure to remove them was "extremely concerning", the charity Electrical Safety First's chief executive Lesley Rudd said.
Wish said sellers on its platform were responsible for their goods' safety.
But it has not responded to a question about why it has not removed the listings now the matter has been brought to its attention.
The dangerous items highlighted in the BBC's Watchdog programme, on Tuesday evening on The One Show, included:
- a scooter charger with an illegal clove-shaped plug
- an extension lead that can cause electric shock
- a hair dryer with an illegal clove-shaped plug
- a travel adaptor lacking safety shutters, leaving internal live components exposed
- hair clippers with a substandard adaptor
- a car-battery charger with an illegal clove-shaped plug
In response to the findings, Wish, which sells more than 150 million different products, told Watchdog it would "take down any products if evidence was shown to prove they were unsafe" and refund customers who had bought them.
But it was up to individual sellers to check products conformed to safety regulations.
Ms Rudd said: "These items pose a serious risk of harm to those who purchase them and are illegal for sale to UK consumers."
She urged the government to step in "to protect online shoppers from the real threat substandard electrical goods pose".
The Online Harms Bill, being considered by Parliament, could be a good place to include legislation about dangerous electrical goods, Ms Rudd suggested.
Previous investigations from Consumer group Which? have found unsafe goods on eBay and Amazon.
And campaigners want the government to make online marketplaces legally responsible for goods sold on their platforms.
Wish has also been repeatedly reprimanded by the Advertising Standards Authority for inappropriately targeted advertising, including an "overtly sexual" ad, with a woman wearing nipple tassels, which featured on the BBC's Good Food Guide app.