Courier company Toll has shut down some of its services after a cyber security breach.

Toll Group, which also provides transport and logistics services, said its IT teams were working closely with security experts.

Toll Group. Credit:Pat Scala

"As a precautionary measure, in response to a cyber security incident on Friday, Toll deliberately shut down a number of systems across multiple sites and business units," a spokesperson said.

Toll has not said how many customers are affected. The company delivers 95 million items around the globe every year, including United States travel documents to Australians.