The phony war between northwest European seaports is drawing to a close as new forces come into play that could alter the balance of power in the Le Havre-Hamburg range.

For years, Hamburg and Belgium's Antwerp have been snapping at the heels of Rotterdam, by far Europe's largest port for most cargoes, from crude oil and iron ore to containerized goods.But so far there has been little change in market share in the Le Havre- Hamburg range, although the North German port received a valuable boost

from the new hinterland gained from German unification and the collapse of communism in Central and Eastern Europe.

Meanwhile, Antwerp continues to capitalize on its productive and flexible longshoremen to bolster its share of conventional cargo, still a substantial market despite the unstoppable march of the container.

Rotterdam remains king, accounting for 38.6 percent of container traffic in the range in 1993 (the latest year for which complete figures are available), down marginally from 40 percent in 1989.

The port's grip on bulk cargoes is even stronger, its 60 percent share dwarfing its nearest challenger, Antwerp, at just below 16 percent in 1994.

And figures for the first half of 1995 show all the big ports sharing in a boom, particularly in containers, as Europe continues to power its way out of the deepest recession in a generation. Antwerp led the revival, boosting traffic by 9.5 percent, or 100,000 20-foot equivalent units, to 1.18 million TEUs. Rotterdam's traffic rose to 2.4 million TEUs from 2.2 million in the year-earlier period, Bremen-Bremerhaven was up 4.7 percent at 757,000 TEUs, and Hamburg surged 6.7 percent to 1.4 million TEUs.

But the stability in rankings is unlikely to last out the decade, as forces beyond the ports' control pave the way for a radical shake-up of trading patterns. Containers are the prize traffic because they add value: They have to be unpacked and their contents forwarded or even assembled.

The biggest challenges are the trends toward ever-bigger container vessels and an ever-smaller number of giant global shipping companies - trends that point inevitably to a concentration on a small number of hub ports. In short, there will be winners and losers in the Le Havre-Hamburg range.

Most intercontinental containerships will range in capacity between 4,500 and 6,000 TEUs within the next five years. In northwest Europe these ships will operate into select hubs, transferring boxes onto feeder vessels for onward shipments to spoke ports in Scandinavia, the Baltic states and even southern Europe.

The front-line victim will be the port that's currently outperforming its rivals: Antwerp.

The port has always been able to compensate for its location on the Scheldt River, at least five hours' sailing from the open sea, with keen freight- handling rates and some of the hardest-working dockers in the world. But its stevedores always knew there would be a day of reckoning no matter how hard they try to minimize their geographic handicap.

This year, the Flemish government signed a treaty with the Netherlands to deepen the channel that passes through Dutch territory before reaching the North Sea. But this won't ease Antwerp's problems. The simple fact is that even after the Scheldt has been deepened, the new generation of giant containerships will be able to enter or leave the port only at high tide. And the additional 10 hours of sailing time is something owners of the hugely expensive ships can't afford.

Even as they notch up record cargo figures, Antwerp's stevedores are taking defensive action, rushing to build new container facilities in the nearby coastal port of Zeebrugge.

What was regarded as an act of treachery when Katoenatie-Seaport, a leading Antwerp stevedore, set up in Zeebrugge four years ago, is now plain good business sense as its rivals move to the coast, following carriers such as Cast, Maersk Line and P&O Containers.

The city of Antwerp, which operates the port, has even floated the idea of taking over Zeebrugge.

Port executives who used to scoff at Zeebrugge's bid to join the big league are now taking the upstart more seriously, although they attribute its success to the lavish state subsidies that finance extremely low handling rates. Those allegations are denounced by Fernand Traen, chairman of the Zeebrugge port authority, as sour grapes.

For the moment, Zeebrugge, which handled just over 600,000 TEUs last year, isn't a major threat to the bigger ports. It still needs to hook a trunk-line service from one of the leading carriers to achieve critical mass and boost its credibility.

The big ports, particularly Rotterdam and Hamburg, looked set to dominate the northwest European container market. But a series of shake-ups in the shipping industry, portending a wave of mergers and alliances, will create a buyers' market that could lead to a bloodbath among cargo-hungry ports.

The recent trail-blazing global alliance between Sea-Land Service Inc. and Maersk Line sent shudders through the ports industry because it expanded the scope of cooperation from straightforward vessel-sharing into landside operations. "Operational coordination will extend beyond line-haul ships to cover terminals, feeder vessels and inland transportation," the two lines said.