Boris Johnson said "delivering value for money is vital"
London's mayor is proposing to cut the Greater London Authority's (GLA) expenditure by 15%.
Boris Johnson said delivering value for money and preventing youth crime were his priorities as he set out the guidelines for his first budget.
Both the Metropolitan Police Authority (MPA) and the London Fire and Emergency Planning Authority (LFEPA) could see increases in their budget for 2009-10.
The mayor will issue a draft budget for consultation in December.
He will then present the draft budget proposals to the London Assembly in January.
Mr Johnson said improving the quality of life for all Londoners was another priority and he has also made it clear new policies must meet his commitment to reduce CO2 by 60% by 2025.
His proposals will see no changes to the budgets of the mayor's business wing, the London Development Agency (LDA) and Transport for London (TfL).
Despite a cut in the GLA's budget of 15% for 2009-10, there will be annual increases of 1.25% in both in 2010-11 and 2011-12.
Both the MPA and LFEPA will see increases of 1.75% for 2009-10 and 1.25% in 2010-11 and 2011-12.
Mr Johnson said: "Crime is the number one issue for Londoners.
"I will build on the early measures I have introduced such as the alcohol ban on the Tube and extra 440 safer transport police officers.
"Tackling the long-term root causes of crime and violence and ensuring a visible police presence on the streets must become the priority for the entire GLA group.
"Delivering greater value for money is vital and it is clear there are a series of areas where the GLA and LDA can be improved and made far more efficient.
"That's why I am proposing a 15% saving in the GLA budget to ensure we are providing maximum value for London taxpayers."
But Darren Johnson, Green Party member of the London Assembly said: "Cuts on this enormous scale puts into jeopardy the GLA's role as a strategic body and its ability to deliver social and environmental improvements.
"The chief executive has made clear that he doesn't think you can meet the mayor's target for savings without stopping some of the vital work City Hall does to improve Londoner's quality of life."