Premier League referee Mark Halsey has made a complaint to Greater Manchester Police after receiving two abusive tweets on Sunday.

The 51-year-old received the insulting messages, which referred to his battle with throat cancer in 2009, after taking charge of Liverpool's 2-1 defeat against Manchester United.

Mr Halsey asked the police to investigate the matter, a spokesman for Professional Game Match Officials Limited (PGMOL) confirmed.

The tweets come just days after the Director of Public Prosecutions said new guidelines for prosecutors on social media cases will be issued after a growing number of complaints.

Last week, a Welsh Premier League footballer who posted an abusive message about Olympic diver Tom Daley was not charged because the message was "not so grossly offensive that criminal charges need to be brought", Keir Starmer said.

But Mr Starmer, the most senior prosecutor in England and Wales, added: "The time has come for an informed debate about the boundaries of free speech in an age of social media."

Halsey made two controversial decisions on Sunday, both of which went in favour of Manchester United.

He sent off Liverpool midfielder Jonjo Shelvey before awarding United a penalty, which was scored by Robin van Persie.

Both tweets, thought to have been sent by disgruntled Liverpool supporters, were met with outrage.

One, from an account named @johnwareing1, read: "I hope Mark Halsey gets cancer again and dies."

The other, from @lfcjohn259, read: "Mark Halsey should've died of cancer."

PGMO, which represents referees and linesmen, said in a statement: "PGMO abhors any abuse of match officials whether that is in stadia or outside of it."

Mr Halsey returned to refereeing in March 2010 after winning his battle against cancer.