Deputy interior minister for security, Gen. Ayub Salangi confirmed the incident and said 3 policemen were injured following the attack.
In the meantime, a local security official said the target of the suicide bomber was the police chief for border protection forces.
The official further added that the incident took place near the border protection police forces central command in Lashkargah city.
No group including the Taliban militants has so far claimed responsibility behind the incident.
Helmend is the among the volatile provinces in southern Afghanistan where anti-government armed militant groups are actively operating.
At least two policemen were martyred and five Afghan national army soldiers were injured following a suicide attack Greshk district on Saturday.