Thongyu Khongkhan, a vice-president of the Thai Logistics Services Provider Federation, said thousands of containers are stranded in Klong Toey and Laem Chabang ports because the factories that ordered the cargo are now inundated.
The cargo comprises raw materials, equipment, machinery, parts and components for industrial production.
"We're asking the PAT to cut rental fees for containers that cannot be moved out of the ports for the time being," said Thongyu.
"These containers are being kept there due to the manufacturing disruption in the inundated industrial estates, while Greater Bangkok has also been hit by the flooding."
As well, the federation has asked the Customs Department not to place imported cargo on the F list – used for overtime cargo – if importers fail to declare the items within 60 days, said Thongyu.
He said the proposal, which was made through the Thai National Shippers' Council (TNSC), also asks the department to provide services around the clock to clear the backlog once the situation returns to normal.
Klong Toey Port in Bangkok and Laem Chabang deep-sea port in Chon Buri province are now both operating as normal after the former suspended services for five days last week due to the high level of the Chao Phraya River.
The two ports together can accommodate 5.5 million containers.
Thongyu, who is also an adviser to the Land Transport Federation of Thailand, said banks are also being called upon to extend the period for packing credit and amend the terms of letters of credit (LCs) for those exporters whose production has been affected by the floods.
"Some exporters may not be able to ship their products on time and need their banks to amend the terms for LCs and packing credit and waive the fees," he said.
Thongyu also noted that shipping lines have declined to operate from the Lat Krabang inland container depot, which is at risk of flooding.
As a result, exporters have had to move their goods from Lat Krabang to a port at their own expense.
TNSC chairman Paiboon Ponsuwanna said his organisation is willing to help coordinate with relevant agencies regarding importers' concerns.
"But we must be realistic. If each company kept their containers in port, then all the space would be full, leaving little or no room for other activities, especially exports," he said.
The TNSC, which comprises nearly 3,000 exporters, has reported a 10 percent year-on-year decline in exports since early last month.
Fourth-quarter exports of the seven submerged industrial estates are expected to fall by 30 percent year-on-year, Paiboon added.