Mr Gubbay, one of the most respected figures in the field, worked a few years ago with the Royal Opera House on a co-production of Turandot.
Yesterday he announced he would be mounting a pounds 1m arena opera production of La Boheme next February with the Royal Albert Hall. He wanted to put it on there, he said, because places like the Royal Opera House and London Coliseum, home of the English National Opera, were elitist and used their money badly.
The rarity of such an attack by an arts practitioner was matched by the extreme nature of the language used.
Mr Gubbay said: "The top price at La Boheme will be pounds 37, compared to over pounds 100 at the Royal Opera House. It has become far too elitist. People go there to be seen, for the interval drinks and for meals in the restaurants round the corner.
"In addition, there are methods of doing things and restrictive practices which don't bear scrutiny at both the Royal Opera House and the Coliseum. Stage hands are getting overtime paid all the time.
"But the nature of theatre work is that you don't work a nine-to-five day. The Royal Opera House are definitely overpaying their backstage staff. Those guys get in some cases more than the performers. I know for example that when something is wanted from the props department two people have to go and they don't work again that day because they have left the theatre. The lottery award of pounds 52m to the Royal Opera House was obscene. There is a need for proper scrutiny and accountability as it might well be wasting a substantial amount of money a year."
Mr Gubbay said the Royal Shakespeare Company was employing "a bunch of actors, none of whom earn more than pounds 500 a week. Why is the company getting all that money? There just don't seem to be the same controls and scrutiny that there is in the commercial sector."
The attack was added to by Patrick Deuchar, chief executive of the Royal Albert Hall. He said that a survey of his customers had shown they wanted opera in comfortable surroundings at reasonable prices.
He said: "There's a strata of society who desperately want to come and enjoy opera but the atmosphere at our opera houses is icy and dismissive."
A spokeswoman for the Royal Opera House said the practices complained of were no longer in existence. "We have the most efficient and cost effective personnel operation in existence."