According to Tolo News, officials confirmed the death toll and said children were among those killed and wounded in the blast.
Helmand governor's spokesman Omar Zwak said the explosion took place outside Helmand stadium in Lashkargah City of the province on Friday when people were leaving the stadium after watching a wrestling match.
Afghan President Ashraf Ghani has condemned the attack and said in a statement that "The enemies of Afghanistan cannot prevent the celebration of traditional, religious and cultural events in the country".
United Nations Assistance Mission in Afghanistan (UNAMA) confirming the incident on Twitter said, "verifying disturbing reports of attack outside a sports stadium in Helmand."
"Attacks directed at civilians are clear violations of international humanitarian law and may amount to war crimes," UNAMA tweeted.
Till now, no terrorist organisation has taken responsibility for the deadly blast.