Annan struck an urgent tone for his reform plan, but acknowledged that getting agreement so quickly would not be easy for the United Nations, where 191 member countries have historically been loathe to sacrifice national interests.
"This hall has heard enough high-sounding declarations to last us for some decades to come," Annan told the General Assembly in an address on Monday. "What is needed now is not more declarations or promises."
His plan tackles some of the UN's thorniest problems and backs some conclusions of two UN-commissioned panels released last year.
It would enlarge the Security Council to include more voices from the developing world and all regions. And it would seek to bring new relevancy to the General Assembly, which has sometimes been hijacked by nations acting in concert to push their own agendas.
The proposals would also try to bring more efficiency and accountability to an organisation burdened by allegations of mismanagement in the scandal-ridden UN oil-for-food programme in Iraq and claims of sexual misconduct by peacekeepers in Congo.
Annan said the next task would be persuading all 191 member states to accept his proposals. He stressed that they cannot be adopted piecemeal.
"It's going to take lots of work, lots of work here in this building with the permanent representatives, lots of work with capitals with the heads of state and government, lots of work by certain envoys that I hope to send out," he said.
"I'll be on the phone also quite a lot."
Several diplomats and government officials said the report was a good start but they wanted to study it more closely.
The US, however, rejected a recommendation that the Security Council adopt a resolution specifying the criteria for decisions on whether to use force.
"It's going to take lots of work, lots of work here in this building with the permanent representatives, lots of work with capitals with the heads of state and government, lots of work by certain envoys that I hope to send out"
"In our view, the UN charter deals with the issue sufficiently," US State Department spokesman Adam Ereli said.
And Russia's UN ambassador Andrey Denisov was sceptical about Annan's plan to do away with the largely discredited UN Human Rights Commission and replace it with a Human Rights Council. He said he was worried it could become another UN "discussion club".
The issue that has got the most attention so far is that of Security Council reform.
Annan backed two options proposed in December - one that would add six new permanent members and another that would create a new tier of eight semi-permanent members, two each from Asia, Africa, Europe and the Americas.
Annan said giving any new members veto power would be politically impossible because the five current permanent council members - the US, Russia, China, France and Britain - would be unwilling to give up their veto power or allow any new veto-wielding members.
"I believe the general sense is that additional vetoes will not be acceptable to the membership," he said.
Likely candidates for the council's permanent members include Japan, Germany, Brazil, India, Egypt, and Nigeria or South Africa.
Later on the day, a joint statement from Brazil, Germany, India and Japan backed the first option for six new permanent members and said they expected General Assembly approval by the summer.