A dossier reportedly showing guns for sale on auction website eBay is to be given to Home Secretary David Blunkett.
Ebay says it is "determinedly" opposed to gun sales
The list, said to cover the last four days, is to highlight concerns Labour MP Steve McCabe has of "unscrupulous" sellers using the site.
The Birmingham Hall Green MP is calling on the government to tighten laws to end the alleged practice.
But eBay said it was "determinedly" opposed to gun sales and already took many of the precautions he suggested.
Mr McCabe said: "EBay...is allowing dealers to sell weapons without any check on whether they are active or not," he said.
"It has no control over the age of people buying them.
"Dealers know that illegal weapons will be removed from the site within 24 hours so they are using that time to advertise private sales or advertising empty bags or boxes for sale and offering guns as a free gift.
"This site is being used to facilitate a trade in illegal weapons. The company is failing to police its own site properly and contributing to crime on our streets.
"I want Mr Blunkett to follow this up with his officials so we can look at how the law is implemented, identify the gaps and tighten it up."
An eBay spokesman said the site was so opposed to gun sales that it had even chosen to ban them in the US, where selling guns is legal.
"We are already taking many of the measures that Mr McCabe suggests and, as soon as he makes himself available to us, we would like to discuss what more we could do," he said.
"EBay acts quickly and decisively on any notification that any item breaches our firearms policy.
"EBay works closely and co-operatively with law enforcement and employs an ex-Scotland Yard police officer as part of our investigation team.
"In terms of the issue raised by Mr McCabe concerning import of firearms from the US, this is not solely an eBay issue but a much wider international trade issue.
"Firearm components could easily be bought off other internet sites or indeed, off-line stores in the US and imported over."
Founded in September 1995 and launched in the UK in 1999, eBay has had a massive impact on global internet trading, with an estimate 25 million items listed for sale every day.