Australian law firm HWL Ebsworth is being investigated by a state workplace health and safety regulator after six of its Melbourne employees tested positive for the novel coronavirus.

"WorkSafe [Victoria] is investigating the coronavirus (COVID-19) outbreak at HWL Ebsworth," a spokesperson for the regulator said, but declined to comment further.

"We have been liaising with WorkSafe in accordance with their standard coronavirus (COVID-19) response process. We have not, however, been advised of any formal investigation," a spokesman for HWL Ebsworth said in a statement, and declined to comment further.