Margaret Beckett, Labour's health spokeswoman, said the move, in which Robert Creighton, 44, becomes chief executive of the Hospital for Sick Children in Great Ormond Street, raised "worrying questions''.
It comes after questions at the Nolan committee into standards of public service about the need for a delay between civil servants and ministers leaving office and being employed.
Mrs Beckett said: "Who gave Robert Creighton permission to move to this post straight from the civil service and why? His appointment raises worrying questions because it will give a big competitive advantage to an already famous and excellent hospital as it enters the competitive market."
But sources close to Mrs Bottomley strongly defended the appointment, denying there was a parallel with the row last week over Lord Wakeham's appointment to a merchant bank. "It is not in the private sector. He had to go through open competition and fourinterviews to get the job and he had relevant experience. Where's the beef?"
Mr Creighton was in Mrs Bottomley's private office for more than two years before being switched recently to take charge of staffing cuts in the Department of Health. Prior to joining her office, he headed the special health authorities' management unit in the NHS executive, which included Great Ormond Street.
He leaves the civil service on 1 April, but joins as the designate chief executive on 13 March for a three-week handover period with Sir Anthony Tippet, who is retiring after eight years.
Defending Mr Creighton's appointment, the Great Ormond Street hospital trust said: "The board is delighted to have someone of his standing, breadth of experience and outlook as the next chief executive."Reuse content