Arrested Canadian naval officer may also have leaked top-level British, American and Australian intelligence documents

Jeffrey Delisle was charged in Canada in January with communicating over last five years 'with foreign entity'

Report today said he may also have compromised British, U.S. and Australian intelligence

Canadian naval officer Jeffrey Delisle was arrested in January for allegedly leaking secrets. It today emerged that he may also have compromised top-level Australian, British and American intelligence

Jeffrey Delisle, a naval intelligence officer, was charged in Canada in January with communicating over the past five years 'with a foreign entity, information that the government of Canada is taking measures to safeguard'.

Canadian reports said Ottawa expelled four Russian diplomats in the aftermath of Delisle's arrest, although Moscow denied this.

Today's Sydney Morning Herald, citing Australian security sources, said Delisle also allegedly sold to Moscow signals intelligence - information gathered by the interception of radio and radar signals - collected by the U.S., Britain, Australia and New Zealand.

It said much of the information was more highly classified than the disclosures attributed to U.S. Private Bradley Manning, who is accused of releasing a vast cache of classified files to whistle-blowing website WikiLeaks.

The newspaper said Delisle was the subject of high-level consultations between the Australian and Canadian governments and was discussed at a secret international conference in New Zealand earlier this year.

An Australian security source quoted by the newspaper said Delisle's access was 'apparently very wide' and that 'Australian reporting was inevitably compromised'.

'The signals intelligence community is very close, we share our intelligence overwhelmingly with the US, UK and Canada,' a former Australian Defence Signals Directorate officer said.

Canadian reports said Ottawa expelled four Russian diplomats in the aftermath of Delisle's arrest, although Moscow denied this

Canadian reports said Ottawa expelled four Russian diplomats in the aftermath of Delisle's arrest, although Moscow denied this

An Australian Defence Department spokeswoman said the government did not comment on intelligence matters.

She said: 'However, the Australian government takes national security very seriously and is continually reviewing and strengthening policies, practices and techniques to ensure Australia's national security.'

New Zealand Prime Minister John Key refused to confirm whether the intelligence conference took place and said he could not discuss matters of national security.

He said: 'I'm not in a position to be able to, or want to, comment on our national security. These things are sometimes better left unsaid.'

Delisle's offences allegedly occurred in the Canadian capital Ottawa, Halifax and in towns in Ontario and Nova Scotia provinces, court documents said.

He has been charged under Canada's Security of Information Act, with a conviction carrying a maximum penalty of life in prison.