NORTH American port congestion has re-entered record-breaking territory despite reductions in ships awaiting berths from 109 vessels to 26 at Los Angeles and Long Beach, reports New York's FreightWaves.

That's because of the build up of 153 idle ships at east and Gulf Coast ports, where 92 vessels wait offshore as of June 10, led by 25 off Savannah, Georgia, 20 off Los Angeles/Long Beach, 18 off New York/New Jersey and 14 off Houston.

Then things got worse. The tally rose to 125 on July 8, 136 on July 13 and 140 on July 19.

With the count rising to 153, the North American containership queue has increased in size 66 per cent over the past seven weeks.

As of Thursday morning, ship-position data from MarineTraffic and the latest queue lists for California ports showed 43 containerships waiting off Savannah; 26 off Los Angeles/Long Beach; 24 off Houston; 18 off New York/New Jersey; 17 off Vancouver, British Columbia; 15 off Oakland, California; and 10 ships off other ports.

Of those, 59 ships - 38 per cent of the total - were waiting off the west coast, where queues have climbed at Vancouver and Oakland. There were 94 ships (62 per cent of the total) off the east and Gulf Coast ports, with counts up in both Savannah and Houston.