A South Australian court has ordered internet giant Google to reveal to a businessman the identities of anonymous bloggers who he claims have defamed him.

Shane Radbone, a former AFL footballer, and his wife Victoria Elise Radbone want to sue the bloggers for defamation and applied to the SA District Court in Adelaide for orders against Google.

Ordered to identify bloggers ... Google.

Master Mark Blumberg on Tuesday ordered Google to disclose to the Radbones, within 21 days, full particulars of "relevant evidentiary material" relating to the identity of the person or persons who registered five named blogs.

The person or persons posted anonymous blogs on Goggle's popular blogger.com. network.