Reports say there has been a major cyber attack on the computers at the Bureau of Meteorology (BoM), and China is to blame.

The ABC says “multiple official sources” have confirmed the attack and its origins in China.

It appears that hackers broke into the bureau’s large network of supercomputers, which are linked with and provide critical information to many government agencies.

BoM’s systems run nationwide, and include a link into the Department of Defence at Russell Offices in Canberra.

Insiders say the motivation for the attack could be commercial, strategic or both.

Earlier this year, BoM chief Robert Vertessy told reporters that the agency was evolving “from what was once just a straight weather service to what I would call now a more broad-based environmental intelligence agency”.

BoM provides weather and climate models, forecasting, tsunami warnings, tide predictions, mapping of water resources and even weather in space.

Its systems are a critical national resource, and contain a vast amount of intellectual property and scientific research that would be of interest to nefarious hackers or foreign states.

If BoM were to be comprised and Australia lost its ability to accurately forecast weather, the operation of military and commercial aircraft would be affected.

There has been no official confirmation of the security breach just yet, but speculation has already begun on how much it would cost and how long it would take to repair one of the largest and most complex government networks in Australia.