Sehore District Collector Kavindra Kiyawat said the injured persons were sent to Hoshangabad for treatment.
The deceased labourers were identified as Seema Gaud (18), Lalita Gaud (18) and Mithilesh Gaud (18), police said, adding they belonged to Daudi village in Betul district.
Congress General Secretary Digvijay Singh who arrived at Ahmedpur in the district for poll campaigning expressed grief about the incident and demanded probe.