“We don't know how many bodies remain at the site and we don't know if it was a suicide attack or a bomb or something else,” he told AFP.
Most of the victims were male as the explosion occurred in an area of the wedding celebrations reserved for men. An AFP reporter at the hospital counted 10 children among the wounded.
The district, located 20 kilometres north of Kandahar city, is considered a rear base for the Taliban. The families participating in the wedding were not considered to have links to the security forces or the civilian administration.
The groom's brother, Mohammad Zanif, said: “My brother was wounded. We don't know what happened. There was an enormous explosion and as a result everyone there was either killed or injured.” Local television appealed for people to donate blood to help treat the wounded.
Kandahar is the focus of a massive build-up by US-led military forces trying to push back the Taliban and end their nearly nine-year insurgency.
Taliban attacks, usually in the form of roadside bombs or gunfights, typically cause relatively few casualties.
By contrast, a number of incidents caused by Western forces have resulted in high civilian death tolls, severely tarnishing the credibility of military operations.
In September up to 90 people were killed in an air strike on fuel tankers in northern Afghanistan.
In November 2008 37 civilians and 26 insurgents were killed by a US air strike on a wedding in Kandahar province.
Wednesday's explosion came during a particularly bloody week for foreign forces in Afghanistan, with 23 international soldiers killed, including four US servicemen who died when a Nato helicopter was shot down in Helmand.
Some observers have suggested the Taliban have been emboldened in their attacks by a “peace jirga” hosted by President Hamid Karzai last week with a view to coaxing militant fighters to lay down their weapons.
The jirga was marred by a rocket attack for which the Taliban claimed responsibility, prompting two of Karzai's top security officials to resign.