Election officials in Bastar district said Kashyap defeated Kawasi by over 85,000 votes to win the tribal-dominated constituency spread over four districts.
A formal declaration of the result will be made soon, they said.
Dinesh is the son of former Bastar MP Baliram Kashyap, whose death necessitated the bypoll held on May 8. Lakma is the sitting Congress legislator from Konta (ST).
Bastar Collector and Election Officer P Anbalagan said counting of votes began on Friday morning amid tight security at the district headquarters at Jagdalpur, where a total of 16 counting rounds were held.
Eight assembly segments of four districts -- Bastar, Dantewada, Narayanpur and Bijapur -- form the Bastar Parliamentary constituency.