The new ASIO headquarters in Canberra has been officially opened but for security reasons the ceremony has been held before staff move in.

The controversial $630 million building on Parkes Way has been plagued by construction delays and finished $170 million over budget.

But the Federal Government insists the building is secure despite an ABC Four Corners report earlier this year that the blueprints had been stolen in a cyber attack.

Prime Minister Kevin Rudd says the facility will also house the Australian Cyber Security Centre and will be dedicated to countering new threats.

"In a world of change, new threats are constantly emerging or evolving - cyber threats, terrorism at home and abroad and people smuggling," he said.

"The technology-dependent world we now live in also presents more challenges and threats. Australia now operates in a world of complex systems, all vulnerable to malicious cyber activity."

The building has been named after former prime minister Ben Chifley.

The Chifley government wrote the charter for ASIO in 1949.

"For all the years that now separate us from Ben Chifley's Australia and ours, his vision for the Australian Security Intelligence Organisation has survived the passage of time," Mr Rudd said.

"The end of the Cold War did not end the threat of espionage and terrorism. We depend on ASIO to protect our democratic freedoms, to deal with terrorism and to combat espionage."

Opposition Leader Tony Abbott also paid tribute to the security experts who will work in the headquarters.

"We do have real enemies, we do face real threats, some of them are internal and they do need to be monitored," he said.

"We only sleep safe in our beds at night because of rough men on our borders and because of smart men and women huddled over computer screens in buildings such as this."