The legislation requires internet service providers and mobile phone operators to block pornography at the network level unless the customer is 18 or over and asks for the block to be removed through an opt-in mechanism.
Baroness Howe of Idlicote, who introduced the Bill in the House of Lords, said the change would help parents to protect their children.
She criticised the "reluctance" to block or limit access to adult content on the internet.
"Historically, most internet content has escaped regulation," she said.
The Bill has been welcomed by Claire Perry MP, who recently convened a cross-party enquiry on the subject of online child safety.
She said: "Our TV viewing is guided by clear Ofcom advice, our cinema screens are subject to British Film Board classifications and high street hoardings and general print advertising are regulated by the Advertising Standards Agency.
"And growing internet enabling of household devices and technological convergence – a quarter of TVs sold in the US are now internet enabled - means that the difference in regulation is going to come crashing into our living rooms."
Some of the most popular internet pornography websites do not have age verification mechanisms in place.
According to Psychologies Magazine, the single largest group of internet pornography consumers is children aged 12 to 17, while one in three 10-year-olds has seen pornography online. The same magazine said that four in every five teenagers aged 14 to 16 "regularly" accessed explicit photographs and movies on their home computers.
A recent YouGov poll pointed to increasing ease of access to pornography, with two-thirds of children admitting that they had accessed explicit material on their handsets.
The Bill coincides with the new Safety Net campaign petition from Premier Christian Media asking the Government to force internet service providers to make accessing pornography "an adult only opt-in service".
The petition has gathered 40,000 signatures in just a few weeks.
Mrs Perry concluded: "The Howe Bill addresses very effectively one of the greatest challenges for UK parents today, protecting children on-line. It is a timely and important piece of legislation that I hope will have a big impact."
On the web: www.safetynet.org.uk/index.php