The SLPA had promised "efficient and fast port services" and "higher productivity" to win the custom of the shipping lines, it said.
"If these procedures were interfered with by any means due to the work-to-rule actions, there exists a risk that these giant shipping lines would deviate to other ports."
This, the SLPA warned, could cause it "a large financial loss" while also affected the proposed salary increment for dockers as well as port development activities.
The SLPA is believed to have given tariff concessions to win over the shipping lines from the rival SAGT, and also promised guaranteed cargo handling speeds to ensure a fast turnaround of ships.
The SLPA statement urged trade unions engaged in the work-to-rule to pay "greater attention to these concerns without being narrow minded".
The dockers' are backing demands by other state sector workers in the petroleum refing and distributing utility, Ceylon Petroleum Corporation, the power utility Ceylon Electricity Boar