Lord Justice Brian Leveson unveils his report following an inquiry into media practices at the QE2 Centre in central London November 29, 2012. Prime Minister David Cameron faces a no-win dilemma on Thursday when a far-reaching inquiry into British newspapers delivers its verdict on how to curb the excesses of the country's notoriously aggressive press.   REUTERS/Dan Kitwood    (BRITAIN - Tags: POLITICS MEDIA)

New laws ... Lord Leveson says the impact of the internet will have to be moderated. Photo: Reuters

UPLOADING a compromising picture can have lifelong consequences but people are unaware of these dangers, says Lord Leveson.

The British peer who led the inquiry into the newspaper phone-hacking scandal in Britain has warned of the potential pitfalls of social media and the internet.

Speaking at a privacy seminar in Sydney on Friday, Lord Leveson said: "Children and the young do not appreciate that uploading a compromising photograph for a laugh can have consequences for the long-term future, because once the photograph is in the public domain, it can be found, copied and reproduced, all, again, at the click of the mouse."

"It will be difficult if not impossible to retrieve every copy and in years to come it is likely that it will still be there for a determined researcher to uncover."

Likewise, he warns that where the internet is used for "naming and shaming" individuals, there is the risk of "permanent and disproportionate" harm being done.

"There is not only a danger of trial by Twitter, but also of an unending punishment, and no prospect of rehabilitation via Google."

He says there is an element of "mob rule" in some corners of the internet, and a view that blogging or tweeting is "publication without responsibility or accountability".

He believes it likely that new laws will need to be developed to moderate the impact of the internet.

Speaking at the seminar, organised by the Communications Law Centre of UTS, Lord Leveson would not be drawn into commenting on his recent mammoth report on the British phone-hacking scandal, saying he treated it as a "judgment", and judges did not enter into discussion on their judgments.

He alluded to the recent nude photographs taken of the Duchess of Cambridge, saying they showed little had changed since the intrusion of the press into the honeymoon of US president Grover Cleveland in the 1890s.

"I will say nothing about the recent Australian intrusion into her [Kate Middleton's] private life while she is in hospital."

The seminar, which is being held at the Shangri-La Hotel, is also being addressed by NSW Attorney-General Greg Smith and Malcolm Turnbull, the federal opposition spokesman on communications.

Opening the seminar, the director of the Communciations Law Centre, Professor Michael Fraser, warned that today's citizens willingly gave to large corporations more information than authoritarian states were able to gather in the past.

He said privacy was a human right because it was a "type of freedom ... an element of personal autonomy and human dignity".

Mr Smith said he remained "agnostic" about the need for a new statute to bolster privacy rights.