The UK Government is providing £1.5million in urgent support to Pakistan where flooding has killed nearly 1,000 people since June.
Thousands have been ordered to evacuate their homes as the heaviest monsoon rains in decades continued on Saturday.
Southern Pakistan has been hardest hit, particularly Sindh province, which has received nearly eight times its average August rainfall.
But many rivers also burst their banks in the north-western Khyber Pakhtunkhwa province.
A state of emergency has been declared in some parts of the country. Millions are affected and at least 700,000 homes have been destroyed.
A United Nations appeal is expected to be launched on Tuesday.
Lord Tariq Ahmad, minister of state for South and Central Asia, said: “The floods in Pakistan have devastated local communities and the UK is providing up to £1.5m to help the immediate aftermath.
“We are witnessing the catastrophe that climate change can cause and how it impacts the most vulnerable.
“My thoughts and prayers are with all the victims and their families, and I would like to pay tribute to everyone involved in the relief efforts. We are also working directly with the Pakistan authorities to establish what further assistance and support they require.
“The UK stands with the people of Pakistan during this time of need.”
Humanitarian aid will go to areas worst-hit by flooding.
The UK previously pledged over £55m to partner with Pakistan to fight climate change and manage water sustainably.
