At least 18 people have died and dozens more fallen ill after drinking contaminated alcohol in Pakistan, officials said.

The victims, believed to be mostly Muslim and Christian labourers, consumed the toxic drink at two parties in the central city of Faisalabad.

Only non-Muslims are allowed to buy and consume alcohol in Pakistan, but many people illegally brew alcohol at home.

The provincial governor has ordered an inquiry into the incident.

Victims fainted after drinking the alcohol at a birthday party and another private event in Faisalabad, authorities said.

Most reportedly died before they could be rushed to hospital.

"The death toll from the two parties has reached 18," senior police official Javed Ahmed Khan told the AFP news agency.

"Around two dozens others are heavily affected by the toxic liquor and battling for consciousness."

Drinkers often buy illegal liquor because legal wine shops are closed during the Islamic holy month of Ramadan.

Locally brewed alcohol has been traditionally available in two forms - kuppi and tharra- in Pakistan.

Buyers are said to often mix the two, leading to a more potentially lethal drink.