Saudi-led air strikes have killed dozens of rebels and civilians in the past 24 hours in Yemen's flashpoint province of Hodeida, medical sources said on Thursday.

Saudi-led coalition warplanes carried out nine air raids overnight on positions of the Shia Houthi rebels in the Red Sea province, local sources told AFP.

The strikes killed 36 rebels and 12 civilians, sources at four hospitals in the provincial capital said.

Fighting between the Iran-backed rebels and the government of President Abedrabbo Mansur Hadi supported by the Saudi-led coalition has intensified in the past few weeks, causing a rise in civilian casualties.

Last week, the UN humanitarian coordinator for Yemen Jamie McGoldrick said coalition air strikes on December 26 killed 68 civilians in Hodeida and the neighbouring province of Taez.

The coalition accused McGoldrick of bias towards the rebels, but did not deny the civilian deaths.

The military alliance intervened in support of Hadi's government in March 2015, after the Houthis took over the capital Sanaa and much of the rest of the country.

But despite the coalition's superior firepower, the rebels still control the capital and much of the north.

More than 8,750 people have been killed since the coalition intervened, according to the World Health Organization.