Pakistan expects to cut its GDP growth projection for the financial year 2022-2023 to 3 per cent from 5 per cent due to the losses, planning minister Ahsan Iqbal told an earlier news conference.
The United Nations has launched an appeal for US$160 million in aid to help Pakistan cope with the disaster.
As well as meeting Sharif and foreign minister Bilawal Bhutto-Zardari, Guterres will tour affected areas during his visit.
Bhutto-Zardari told a news conference after the meeting that Pakistan was waiting for the rescue and relief phase of the crisis to end before calling a donor conference to work on reconstruction.
“When we have a 100km lake that has developed in the middle of Pakistan, tell me how big of a drain can I build to manage this?” he said.
“There is no man-made structure that can evacuate this water.”
In July and August, Pakistan recorded 391mm of rainfall – nearly 190 per cent more than the 30-year average. The southern province of Sindh has been overwhelmed, with 466 per cent more rain than average.
Guterres said the world needed to understand the impact of climate change on low-income countries.
“It is essential for the international community to realise this, especially the countries who have contributed more to climate change,” he said.
The World Health Organization has said more than 6.4 million people need humanitarian support in flooded areas.
The cost of clearing up and rebuilding after the floods has added to concerns about whether the country can afford to keep paying its debts.
Over the last three weeks its government bonds have fallen sharply, to almost half their face value in some cases, as international investors have begun to fear a default.