Neptune Orient Lines Ltd.’s APL Ltd., Southeast Asia’s largest container line, and partners will reduce capacity on transatlantic routes by about a third amid slowing world trade.

APL, Hyundai Merchant Marine Co., Mitsui O.S.K. Lines Ltd. and A.P. Moeller-Maersk A/S will make the cuts from December, according to a joint e-mailed statement sent to reporters Thursday.

Container lines have parked ships, delayed orders and fired staff as slumping demand hammers rates.

About 10 percent of the world’s container-ship fleet is laid up because of a lack of cargo and more vessels will likely join them, according to Um Kyung-A, an analyst at Shinyoung Securities Co. in Seoul.

During the forthcoming off-peak season, Asia-Europe rates may fall as much as 40 percent, and by as much as 20 percent on transpacific lanes, according to Johnson Leung, a Hong Kong- based analyst at Tufton Oceanic Ltd., the world’s largest shipping hedge-fund group.

Container lines worldwide may lose at least $20 billion in 2009, the Transpacific Stabilization Agreement said on Oct. 7, citing Drewry Shipping Consultants Ltd., as an increase in new vessels has created a capacity glut.

Shipyards have container-ship orders in hand with a combined capacity equal to about 37 percent of the existing global fleet, according to data compiled by Bloomberg. (Bloomberg)