The company which runs the Manus Island detention centre is investigating reports that one of its guards used Facebook to mock an asylum seeker who self-harmed on Christmas Day.

Darren Powell, who works as a supervisor at the G4S security company, posted an update on Facebook saying an asylum seeker had swallowed a pair of nail clippers.

"Merry Christmas all. One of these jokers just swallowed a pair of nail clippers. RALMFAO," he said.

One of Mr Powell's friends, Jason Drain, who also reportedly works at the Manus Island centre then commented: "I want to be his escort to the shitter when he passes them".

The post now appears to have been removed from Facebook.

According to an online professional profile, Nr Powell has completed suicide prevention training, and as a supervisor is required to ensure that 'clients' are treated with dignity and respect.

G4S, which runs the Manus Island centre, says the matter will be investigated and that its highest priority is the health, safety and welfare of asylum seekers.

Darren Powell is a guard at Manus Island detention centre. ( Facebook )

"G4S is very concerned by reports of recent inappropriate comments on a social media network," the company said in a statement.

It also said the alleged behaviour is a breach of its code of ethics and social media guidelines.

G4S has told The World Today that it will review relevant training programs following the incident.

A spokeswoman for Immigration Minister Scott Morrison says it is completely inappropriate to mock self-harming behaviour.

"The department has asked G4S to investigate this incident and provide a report," the spokeswoman said in a statement.

"Action taken regarding individual employees is a matter for G4S after their investigation."