Shipping union officials yesterday blamed inadequate infrastructure at the country's ports for a spate of ferry collisions over the past month as two cruise ships, carrying more than 3,000 passengers between them, collided off Piraeus. No one was injured in yesterday's incident, which saw the Zenith, a Maltese-flagged cruise liner, ram a moored Greek cruise ship, the Aegean Pearl, while it was trying to dock. The Zenith had been carrying 1,819 passengers and 619 crew and the Aegean Pearl 504 passengers and 349 crew. The Aegean Pearl sustained minor damage from the jolt, while the larger Maltese vessel emerged relatively unscathed, according to Port Authority officials. The collision, the fourth such incident in the Aegean within a month, fueled criticism from shipping union representatives who said that the inadequate coordination of crew members and human error were less of a problem than the poor infrastructure at Piraeus and other ports. «Most ports do not have adequate piers and are not large enough to accommodate large cruise ships,» Achilleas Tarlamis, the general secretary of the Masters and Mates' Union of the Greek Merchant Marine, told Kathimerini. But Tarlamis appeared to suggest that the sudden increase in frequency of ferry collisions was not a cause for concern. «Such minor accidents have always happened - there has been no dramatic change - it is just a bad coincidence that so many occurred within a brief period of time,» he said. Yesterday's collision was the fourth within the past month. Last week a ferry carrying 295 passengers struck a reef off Kythera, south of the Peloponnese, and another ferry hit a moored vessel off Andros. At the end of last month, a passenger ferry hit a rock off Oinousses, in the eastern Aegean. In all cases, the vessels were damaged but there were no reports of any serious injuries.