At least 17 people including a bridegroom and two children drowned Sunday when a rescue boat carrying a wedding party capsized in flood-hit central Pakistan, officials said.

The boat, which was carrying at least 40 people, went down as it attempted to cross a swollen river in the Muzaffargarh district of central Punjab province, they said.

"We have recovered more dead bodies. The death toll has now risen to 17, two women were among the dead," a senior rescue official told AFP, adding the search operation was ongoing.

Local government official Shaukat Ali earlier told AFP that 22 people had been rescued.

Ashiq Malik, medical superintendent of the nearby Nishtar Hospital, said the bodies of two children and bridegroom Zahid Ali, 27, were brought there.

Most passengers were members of a wedding party that had requested the use of the rescue boat to take them to a Valima, an Islamic wedding reception to mark the consummation of a marriage.

"I saved my life by holding on to an electricity pole," distraught bride Mashal told private news channel Samaa TV.

Pakistan's President Mamnoon Hussain expressed "profound grief and sorrow" at the incident in a statement released by his office. Ali, the official, said an enquiry had been ordered.

Jam Sajjad, a spokesman for Punjab's rescue service, claimed the party wanted to the charter the boat despite warnings about the dangerously high waters.

"The family requested to cross the flooded river in the boat and were refused by military officials several times but they kept insisting," he said.

"The waves were moving fast and the family and other people panicked. They were asked to remain calm but they continued to panic, causing the boat to become unbalanced and capsize."

Floods and landslides from days of heavy monsoon rains have now claimed almost 500 lives in Pakistan and India.

Pakistan, which has suffered a series of annual flood disasters since 2010, says as many as 2.3 million people have been affected.

Rescue operations Sunday were concentrated around the central city of Multan, home to two million people, where authorities blew up two dykes to try to stop the water inundating the city.

Some 300 villages around Muzaffargarh have been inundated and the flooding has also devastated thousands of acres of the cotton crop.