The Napthine government has been ordered to fully defend itself in court against accusations it misled the public on the benefits of the East West Link.

Brunswick resident Anthony Murphy is challenging the $6billion-$8billion project in the Supreme Court. His lawyers, who include former Federal Court judge Ron Merkel, QC, argue the project has been based on ''misleading representations'' that breach consumer protection laws.

Tony Murphy is taking the state government to court to try and stop the East-West Link tunnel being built. Credit:Justin McManus

''Whilst the government is fully entitled to construct and operate a tollway, it's not entitled to do it in breach of the public duty not to engage in misleading conduct,'' Mr Merkel said.

He said the government's business case for the East West Link was ''shrouded in secrecy'' and did not detail how the economic benefits of the project were calculated.