High-profile Sydney solicitor Leigh Johnson has been rebuked by the state's highest court and blocked from recovering more than $2 million in legal fees from two elderly clients, with the court saying the bill appeared "out of all proportion" with the amount of work done.

In a scathing judgment delivered on Friday, the Court of Appeal said Ms Johnson "represented that she would not seek to recover any additional legal costs" from her clients before a bill was sent in March last year, some six years after she acted for them successfully in a court case.

Sydney solicitor Leigh Johnson. Credit:Peter Rae

The court noted the bill included "numerous items ...totalling over 24 hours on the same day" and "there is nothing to suggest any other lawyer than Ms Johnson" was working on the case at the time.