Internet service providers have been urged to publicly declare whether they block the use of websites containing child pornography.
Many companies already block access to child porn websites
Labour MP Margaret Moran says she has support from MPs of all parties for a law compelling such companies to publish their policies.
But the Home Office has said it would prefer the industry to regulate itself.
Around one in five internet service providers have not declared whether they block child pornography sites.
The Internet Service Providers Association (ISPA), which has around 130 members, has said that the major companies already prevent access to such websites.
And some companies are thought to not publicise the practice to make it harder for paedophiles to bypass filter systems.
Ms Moran, the Labour MP for Luton South, is expected to introduce the Control of Internet Access (Child Pornography) Bill later in a bid to compel these companies to alter their approach.
Her bill has been put forward under the ten-minute rule, which means it will be the subject of a brief debate on the floor of the Commons, but has no prospect of becoming law.
Under her proposals, companies providing internet access would be required to state, either on their websites or in their annual accounts, whether or not they allow access to child porn by users of their services.
'Name and shame'
She said: "We know that there are many internet service providers that are doing a very good job in trying to prevent internet child pornography.
"My bill is really to ensure that we take the swiftest possible action to encourage internet service providers to use the existing technology to stop these images being relayed to those people who wish to see them, and are contributing to the child pornography trade.
"For every day and every week that we delay making sure that these images are not relayed, there are more children being abused."
BBC Crime Correspondent Neil Bennett said the MP has threatened to "name and shame" companies who fail to disclose their practices.
Most illegal child porn sites, he said, are monitored by police and are thought to be run from the US and Eastern Europe.