With his funds frozen by the courts, Mr Dotcom said Mr Lentino was a close friend who had helped pay his rent.
Mr Lentino has been named as the largest of three Mega investors. The others are from Luxembourg and Australia.
Mr Dotcom tweeted yesterday that the Mega launch had been a success, with 250,000 registrations and servers still functional - but close to overloading.
The appearance of Wellsford-based Mr Lentino in the Dotcom saga has surprised many in the business world. Hawke's Bay resident and Xero founder Rod Drury has been reported as saying he had never heard of him.
Australian Brian Clarkson has taken the reins from Mr Lentino as Instra Corp CEO, so Mr Lentino can concentrate on Mega.
He said it was not surprising few had heard of Mr Lentino.
"Tony has always taken a low profile - he says he values his privacy," he said.
"One of the things that has attracted him to Mega is that it's a service that is about privacy. There is a resonance."
Instra is handling the customer support service for Mega out of its office in the old Public Trust Building in Tennyson St.
"That's where the call centre is, where they will answer email inquiries, field all questions people have at that site and field all the questions on how to use it. Any issues people have, that's where it is handled."
He said Mr Lentino's two sisters and mother work in the Napier office.
The company was very profitable, with most business with overseas entities, he said. "There is certainly a lot of family involvement but it is certainly bigger than a family business."