Mr Johnson said he was dismayed he had to take a decision on the fate of the previous mayor's staff - believed to number eight - who were on fixed contracts.
In a statement his office said: "He feels he is not best placed to do so and that the law is flawed on this issue.
"Employment rights for these members of staff overtake the GLA Act which states they are on fixed contracts, hence the position the current mayor finds himself in."
The statement adds that Mr Johnson wanted to make clear he had no problem with the staff who had served the previous mayor well.
It went on: "The mayor has followed legal advice on this matter and made a decision with the taxpayer in mind. He did not want to expose the organisation to further costs down the line.
"Advice has been clear and consistent. These members of staff are entitled to these settlements. They are only receiving what they are entitled to. Some members of staff have over 20 years loyal service in local government and payments were agreed with this in mind.”
Meanwhile, Mr Johnson has named the board of the London Development Agency. The incumbent chair, Harvey McGrath, remains in the position.