Two clubs from neighbouring towns in the tournament ranked first class by the ICC, the Kalutara Physical Training Culture Circle and Panadura Sports Club have allegedly fixed a three- day game last week.
It was alleged that on the final day, hit by rain, both sides had seen 24 wickets falling for a run rate of over 10 runs an over.
In 20 minutes 13 overs were bowled.
Both clubs figure influential members of the current SLC administration, the complainant Sri Lanka Ports Authority said.
SLC said strong action would be taken against wrong doers.
An independent panel would be appointed to investigate.