The Australian government unwittingly committed a “monumental” security lapse when it sold two file cabinets chock full of classified documents — to a second-hand furniture store.

A junk store in the nation’s capital, Canberra, sold the two locked cabinets at a discount because they were heavy and the keys were lost, but the enterprising new owner drilled open the drawers to discover they were bursting with a year’s worth of classified intel, including papers marked “Top Secret” and “For Australian Eyes Only,” the Australian Broadcasting Corporation reported.

The so-called Cabinet Files revealed for the first time other embarrassing lapses in information security.

The Australian Federal Police separately lost some 400 sensitive documents related to security, intelligence and defense between 2008 and 2013, the Cabinet Files showed, according to the ABC.

And someone left 200 classified papers in the office of senior minister Penny Wong when a new government took power following the 2013 elections there. Some were marked top secret and others code-word-protected — the highest classification of sensitivity, according to reports.

Australian leaders were outraged by the breach.

“Certainly someone needs to pay a price, there needs to be some consequence for what is a monumental lapse,” said former Prime Minister Tony Abbott, whose own administration’s foibles were laid bare in the Cabinet Files.

The documents show that Abbott once considered yanking welfare from anyone under 30.

Others show he handed over sensitive information to a workplace safety investigatory committee despite top administration attorneys’ warnings not to.

Abbott suggested a “relatively junior or mid-ranking departmental officer” sold the cabinet without realizing it contained national secrets.

But Rory Medcalf, head of the Australian National University’s National Security College, told news.com.au that the source was likely high up the food chain.

“The size and high classification level of this cache of documents suggest it came either from the office of a minister or quite a senior official — this is material that junior public servants typically would not handle,” he said.

Prime Minister Malcolm Turnbull has ordered an “urgent investigation,” the Washington Post reported.

Australia currently is facing its highest threat of espionage and foreign interference since the Cold War, the Telegraph reported, citing the Australian Security Intelligence Organisation.

“While that was obviously a very busy time in that period of history, our assessment is that it’s not on the scale of which we are experiencing today,” ASIO deputy director Peter Vickery recently told a government committee.