Ms Haigh said she was involved in scruitinising the Offensive Weapons Bill last year, which bans the online sale of bladed articles to reisdential addresses.
But she added the bill ‘completely fails to tackle the huge array of illegal weapons that are sold on online platforms’ such as Amazon and eBay.
Ms Haigh, who is also the shadow policing minister, said: “Weapons that are already illegal under UK law remain freely available on platforms such as Amazon, eBay and Facebook Marketplace.
“Knives that are disguised as credit cards, bracelets and knuckle dusters can be bought for as little as 99p.
“The government will never be successful in their efforts to limit access to these illegal disguised weapons unless they are prepared to deal with online platforms.
“I find it bizarre that the Government is putting so many burdens on small businesses, while failing to take on the tech giants that are profiting from the sale of such horrendous weapons.”
Ms Haigh’s comments come as a police campaign – Operation Sceptre, aimed at reducing knife crime – continues across the country.
She added: "Never, since records began, has police-recorded violent crime been as high as it is today.
“Dealing with violent crime requires that the Government take a holistic approach, which should include preventing the sale of illegal weapons, particularly to children.
“The existing legislation is clearly not remotely sufficient, given the proliferation of weapons that are available on online platforms now.
“As long as this remains the case, I’ll continue to press the gvernment to put meaningful measures in place to prevent these weapons from being used on our streets.”