Australia is likely to have military assets in the South China Sea to gather vital intelligence on a joint drill between Chinese and Russian forces next month, Fairfax Media understands.

The exercise between Chinese and Russian ships and planes is intended to send a signal of defiance to the West but defence sources and experts say it will also provide a gold mine of intelligence on how the major powers' militaries work together.

A Defence source told Fairfax Media that assets were expected to be used to collect information, though the source declined to say what kind.

"It would be foolish for Defence to miss an opportunity like this," the source said.