An explosion at a market in the home city of Philippine President Rodrigo Duterte killed at least 10 people on Friday and wounded dozens more, his spokesman said, adding the cause of the blast was unknown.

Duterte was in Davao on Friday, but was safe and at a police station after the explosion, his son Paolo Duterte, who is vice mayor of the city, told Reuters.

The incident took place at a street market outside the high-end Marco Polo hotel in Davao, in the southern Philippines, a military spokesman told reporters by phone.

A police official said at least 30 people had been hospitalised.

Presidential spokesman Ernesto Abella told CNN Philippines that some 60 people were wounded and 10 confirmed dead.