The strikes hit a bottling plant in the province on Sunday morning. Most of the dead were civilians.
The coalition is targeting Shia rebels known as Houthis.
The UN says almost 4,500 people have died since the coalition started its campaign in March and that there is now a humanitarian "catastrophe".
"The process of recovering the bodies is finished now. The corpses... many of them burnt or in pieces, were pulled out after an air strike hit the plant," resident Issa Ahmed told the Reuters new agency from the site of Sunday's strike in Hajjah.
Also on Sunday, the head of security in the southern port city of Aden, Abdelhakim al-Sanaidi, was shot dead by unidentified gunmen.
A power vacuum has taken hold in the city since pro-government militiamen recaptured it in July. Officials say Al Qaeda militants have moved into one of the city's neighbourhoods.
Last week 65 people, most of them civilians, were killed in coalition air strikes in the city of Taiz, Medecins Sans Frontieres (MSF) said, which has also seen heavy fighting between rival forces.
The UN says that almost 4,500 people - including 1,950 civilians - have been killed since 26 March, when the Saudi-led coalition began an air campaign to defeat the Houthis and restore President Hadi.
Yemen crisis: Who is fighting whom?
Meeting the Houthis and their enemies
Yemen's humanitarian catastrophe
An air strike by the Saudi-led coalition backing pro-government forces in Yemen has killed 31 people in the northern province of Hajjah.