If Ms Zambello agrees to come to the ROH it will be the first time that a British national arts company has been run by two Americans, an indication of the change of ethos and approach that chairman of the ROH, Sir Colin Southgate, wants to instigate.
Mr Kaiser, known in the US as "the turnaround king" has been at the ROH for three months and has already set in motion various changes, including expanding the base of corporate and individual support, planning a re- opening festival for the opera house and drawing up a new ticket-pricing structure with much lower prices at weekends.
Although Sir Colin said last year that an artistic director would lead the managerial structure, Mr Kaiser has made it clear that he will serve as a joint number one but not as a number two. One early choice for the post of artistic director, Sarah Billinghurst of the Metropolitan Opera in New York, refused to take up the position under that condition.
But it is understood that Ms Zambello is happy with the arrangement and would not want to extend her remit from the artistic side, nor necessarily to be seen as the most senior figure at the ROH.
Insiders say a Zambello/Kaiser ticket could proceed without any bickering.
Her work is already well known to British opera and theatregoers. Her flamboyant production for The Royal Opera of The Bartered Bride is currently on at the Sadler's Wells and she recently put Mussorgsky's Boris Godunov on stage at the London Coliseum for ENO, rehearsing both productions at the same time.
She also directed the revival of the play Lady In The Dark at the National Theatre last year. She has a reputation for handling large casts well and inspiring loyalty.
Ms Zambello, who speaks French, German, Spanish, Italian and Russian, said in a recent interview: "I am a nurturer. Some directors are conceptualists, some authoritarians, some work through total democracy and discovery.
"What I try to do is ensure that everyone involved makes a personal investment and is valued for it."
Ms Zambello could expect to be paid the same salary as Mr Kaiser. He is understood to be earning pounds 115,000 a year with the Royal Opera House.
A Royal Opera House spokeswoman would only comment: "We are searching very actively for an artistic director."Reuse content