Nazi swastikas carved on rocks near a Sydney walking track are among the remains of a little-known German spy camp in suburban bushland.

Today there is little left of the camp at Deep Creek in Narrabeen on Sydney’s northern beaches which once consisted of a hut, tents and small gardens, built in the 1930s to house German sailors from merchant ships docked in Australia.

But if you look carefully, swastikas and the names of German towns and cities with the dates of their inscriptions can be seen carved into rocks.

They’re an eerie reminder just how far the power of Hitler’s Third Reich extended – in this case 16,000 kilometres from Berlin.

And while the Deep Creek camp was officially there to promote German culture as a ‘home away from home’, in reality it was a front for more sinister activities.

One of the carvings made by German sailors in 1938. Stassfurt is the name of a German town. (Nine)

‘SPIES EVERYWHERE’

Sydney writer Greg Clancy has studied Nazi espionage in Australia and told nine.com.au how the camp was part of the German intelligence network in the years before World War II.

“They had spies all around the world – and Australia was no exception.

“The Germans were keen on learning the movement of Australian and British ships in this part of the world, industrial production and Australia’s defences.

“The seamen would gather at the camp and relay what they had learned. It would then be transmitted to German authorities by radio.”

The camp on Sydney's northern beaches was part of Nazi Germany's global espionage network. (Nine)

Mr Clancy said he had seen evidence that showed the camp was run by hardline Nazis.

“There are files in the National Archives compiled by the people who ran it, detailing every activity. At the end of every report it is signed ‘Heil Hitler’.”

‘KEPT IN LINE’

Mr Clancy also says the camp also played a role in keeping German sailor indoctrinated to Nazi beliefs.

“The big wigs in Germany were worried about these seamen being exposed to western, liberal values in countries such as Australia. To keep them in line, they put a hardline Nazi from the feared Gestapo [secret police] on every ship.

“They were there to ensure that every sailor toed the party line.”

This stone fireplace in bushland was part of the camp visited by German sailors in the 1930s. (Nine)

‘FLOGGINGS’

The brutal treatment of any visiting German who strayed from the party line was revealed in a newspaper report after World War II.

The Canberra Times in August 1945 wrote of the “German Gestapo headquarters” at Narrabeen.

“It was used for flogging German sailors from merchant ships who were anti-Nazi in activities,” the report said.

Those who were flogged were too scared to report it to Australian authorities out of fear for reprisals against their families in Germany, the Canberra Times wrote.

RAIDED

By the late 1930s, Australian security services had been alerted to the Deep Creek camp and had it under surveillance.

When Australia declared war against Germany in September 1939, authorities raided it and interned its members.

“The Australian intelligence community certainly knew about Deep Creek years before war came. But they could do little about it until we were officially at war,” Mr Clancy said.