The Commerce Commission questions that claim, however.
"It's not true that they gave us all their company information including fees modelling before their launch," a Commerce Commission spokesman told the Herald.
"They have also never produced their legal advice despite our requests for it."
Harmoney hit back, saying MBIE corrospondence released under the Official Information Act and emails proved the commission was consulted on fees and other aspects of its business prior to the launch.
Harmoney charges a platform fee of $375 to borrowers of all risk grades and loan amounts.
Harmoney chairman David Flack said he was committed to ensuring Harmoney, New Zealand's first licensed peer-to-peer platform, complied with all laws and regulations.
"It is disappointing that the Commerce Commission is seeking to clarify the legal position - as it affects the entire peer-to-peer industry - by bringing this case stated action by using Harmoney's operating model as the basis for the judicial review," Flack said.
He said it was "highly problematic" when interpretation of each law by government departments resulted in a lack of clarity around how regulations applied to peer-to-peer platforms.
"For this reason we have also met with the Commerce and Consumer Affairs Minister Paul Goldsmith to request that is issue be clarified by an appropriate legislative change."
In a separate action, the Commerce Commission has filed Fair Trading Act charges in the Auckland District Court alleging Harmoney misled users into believing they had been approved for personal loans.
Harmoney reported a loss of $14.2 million from revenue of $8.6 million in the year to March 31, 2016.
"Thousands of New Zealanders borrow and lend every day on the Harmoney platform and we have gone about building, launching and operating the platform in exactly the manner anticipated by the new legislation that made p2p platforms possible in New Zealand," Roberts said.
"Harmoney has built a highly transparent and interactive marketplace since it became the first operator in this new area of financial services in New Zealand."