The office was responding to a story on the right-wing Whaleoil blog by Cameron Slater stating that Mr Brown's office had covered up a secret trip to Hong Kong - and that the Hong Kong trip was only made public after several requests were made under the Local Government Official Information and Meetings Act (LGOIMA).
The article questioned Mr Brown's ethics, financial prudence and honesty.
The Whaleoil blog broke the story about Mr Brown's two-year affair with Bevan Chuang, who was a member of the council's ethnic peoples advisory panel.
The Taxpayers' Union was also upset about the release of details about Mr Brown's trip to Hong Kong.
Union executive director Jordan Williams said it appeared from LGOIMA requests to the council on the matter that council officers "deliberately misled'' about the existence of the trip to avoid scrutiny.
"In addition, Auckland Council staff have apparently been instructed not to speak about the particular trip and to refer all inquiries to the mayor's office,'' he said.
Mr Brown's office said that on October 19, Mr Williams asked Auckland Council who the interpreter was that travelled with the mayor on his last trip to China in April 2012.
The interpreter was Yan Zhang - the director of KPMG's China practice.
"The council was not asked this question in relation to his trip to Hong Kong this year or anywhere else,'' the mayoral press release said.
