Australian PM Malcolm Turnbull is known for his enthusiasm for communications technology

The office of Australian Prime Minister Malcolm Turnbull has defended his use of a private email server for government business.

Mr Turnbull's spokesman said many officials used such private systems for their convenience and functionality.

It comes after the The Australian newspaper revealed the PM was using a private email server to communicate with colleagues and journalists.

The report prompted concerns over the security and ethics of the practice.

Some experts have suggested the private email server could be more vulnerable to hacking than the federal parliament's secure system.

The use of a private system has also raised suspicions over whether it could end up subverting freedom-of-information laws.

'Routine correspondence'

In a statement, the PM's spokesman said all communications relating to government business, with exemptions, were potentially subject to freedom of information laws, regardless of where they were stored.

The spokesman said many MPs and ministers used private messaging systems for "non-sensitive material for reasons of convenience and superior functionality".

"The majority of government correspondence is routine and of a non-sensitive nature and is therefore not subject to sensitive security markings," the spokesman said.

The spokesman added that the private email server used by Mr Turnbull was located in Australia.

While he was a minister, Mr Turnbull said he used the Wickr messaging app for its security features. Wickr says its messages are encrypted and self-destruct so they cannot be traced.

In the US, the Democratic Party's presidential hopeful, Hilary Clinton, has faced heavy criticism over her use of a private email server to conduct government business, including sending classified emails.