Clarification is needed on the law around "revenge porn" and when it could lead to a prosecution, a committee of peers has said.

The online trend involves people posting sexually explicit pictures and videos of their former partners on websites and social networks once they have split up.

Last week Justice Minister Lord Faulks admitted that revenge pornography was a growing problem and said the Government was urgently considering the possibility of new laws to tackle it.

And now the House of Lords Communications Committee, in a review of the laws on social media crime, has called on the Director of Public Prosecutions to clarify when the practice becomes a criminal offence.

In the inquiry report they said: "We wo uld welcome clarification from the Director of Public Prosecutions as to the circumstances in which an indecent communication could and should be subject to prosecution under Section 127 of the Communications Act 2003 or Section 1 of the Malicious Communications Act 1988."

The peers said that current laws, most of which pre-dated social media such as Facebook, Twitter and YouTube, were "generally appropriate" and prosecutions could be brought under the Communications Act 2003, Malicious Communications Act 1988 and the 1997 Protection from Harassment Act.

The report also outlines some measures to greater protect victims, pointing to schools, parents and the social media sites themselves.

The committee, chaired by Lord Richard Best, said: "We encourage website operators further to develop their ability to monitor the use made of their services. In particular, it would be desirable for website operators to explore developing systems capable of preventing harassment, for example by the more effective real-time monitoring of traffic.

"Our inquiry is limited to consideration of the law. It strikes us though that parents and schools have a responsibility generally to educate children: children need to be taught that being horrid online is just as wrong and hurtful as being horrid face to face."

Lord Faulks has called the practice "cowardly and despicable" and peers called for a clause to be inserted into the Criminal Justice and Courts Bill.

Lord Best told the BBC Radio 4 Today programme: "We don't think it is about changing the law. There are a lot of laws that could be used."

He said the guidance was "good" but insisted it could be better, particularly in relation to revenge porn "so people know where they stand and don't cross the line".

He went on: "We were astonished at the scale of social media. One and a half billion people on Facebook, 500 million tweets a day.

"One could not possibly police all of this but in extreme cases prosecution must follow.

"We need to know who is responsible... and get to them."

Asked how this could be done in practice, Lord Best admitted it was "extraordinarily difficult".

But he added: "Some of the websites are better than others in requiring people to register with them and keep track of real names."