A complaint has been lodged after Ken Livingstone admitted documents were shredded ahead of new disclosure rules under the Freedom of Information Act.
The Mayor was accused of showing 'arrogant contempt' for the rules
The mayor said many papers were "lost during shredding week just before 1 January 2005", in a response during mayor's questions last month.
New rules made it illegal to destroy data if a valid request had been made.
The Liberal Democrats said they had lodged a complaint with Information Commissioner, Richard Thomas.
Leader of the London Assembly Lib Dems Graham Tope, said it was important the mayor did not "hide the decisions that affect Londoners in a wall of secrecy and silence".
He said: "Some of the key decisions since Ken Livingstone took office have cost London taxpayers hundreds of millions of pounds and yet we have been told very little about them.
"It is deeply worrying that the mayor has shown such arrogant contempt for the new Freedom of Information laws."
Mr Livingstone was challenged by Sally Hamwee over his office's inadequate replies to requests for papers.
His response was to advise members to be more precise when making requests and added there was "almost nothing juicy in there - we never minute anything interesting".
The mayor's office said: "The Greater London Authority (GLA) takes its responsibilities under the Freedom of Information Act extremely seriously.
"It is incorrect to say that little is known about the mayor's policies".