Despite killing 73,000 people in Pakistan, the disaster has failed to elicit the same outpouring of support from the world community as the Indian Ocean tsunami and Hurricane Katrina did earlier this year.
"We received some resources, but need much, much more to be able to help the people," Mr Annan said on arrival in Pakistan for an international donors' conference.
Saturday's conference, to be attended by the World Bank, Asian Development Bank and other lenders, representatives from foreign governments as well as corporate leaders, will focus on the long-term task of reconstruction and rehabilitation.
The estimated cost for rebuilding roads, housing, schools, hospitals and the civil administration, and restoring people's livelihoods is put at €4.4 billion. Yet, so far, Pakistan has had just over €255m pledged toward these tasks.
"I would expect the world, those with capacity, to give generously and give willingly, and I'm not just speaking to the governments but also to the private sector and individuals who can contribute," Mr Annan said.
US President George Bush, in a telephone call from South Korea where he is attending an Asia-Pacific Economic Co-operation forum, promised President Pervez Musharraf that he would help raise awareness of Pakistan's plight.
The devastation affected 3.3 million people and left hundreds of thousands homeless, with winter fast approaching in the Himalayan region.
International support for the rescue and relief effort in the weeks after the October 8 quake won Pakistan's gratitude, but UN aid agencies have warned they would have to wind down vital helicopter relief missions unless they got more money soon.
People in the mountains remain vulnerable with the winter closing and there are also fears of disease spreading in squalid tent settlements that have sprouted in the towns.
Mr Annan, who had warned that there could be a second wave of death unless the world woke up to the scale of the disaster, said more lives would have been saved if aid had arrived faster.
But the UN has been criticised too. US goodwill envoy Karen Hughes said this week on a visit to Pakistan that the UN could be doing more, and aid group Oxfam reckoned that the UN lacked manpower on the ground.
"We need a huge upscaling of the UN response," said Ben Phillips, South Asia policy coordinator for Oxfam, said.
"Our main criticism is of the donors for not giving enough money and of the UN for not sending in enough people," he said.
Just as the UN secretary- general arrived in Pakistan, 24 elderly Kashmiris went home to the Indian side of Kashmir. It was the first movement of people across the disputed border since the quake struck almost six weeks ago.
Pakistani officials say they expect more people to be allowed to cross both ways at all the border points later this month.