The Spaniard thinks it is unacceptable that drivers have to conserve their rubber even on qualifying laps, as they had to do in Korea on Saturday.
But although unhappy about the state of the tyres, he thinks Ferrari would be suffering even more against the opposition if Pirelli was producing rubber that was far more durable.
"I think the tyres are what they are at the moment - and it is a tyre that cannot do five kilometres," said Alonso, who has qualified sixth at Yeongam. "The quality of the tyres is on the limit.
"It is the same for everybody and I am sure all the cars, if they pushed 100 per cent from the start of the lap, they would not last 5km. So this is not very helpful, and it is not very nice to drive like this for 95 per cent of the lap."
He added: "I am not blaming the tyres. But they are not good. We all see with our eyes. But it is the same tyres for everybody.
"I am sure if we put a tyre that could do more than 5km they [Ferrari's rivals] would be even faster in the last sector as well, so it is a compromise we need to find."
Although Alonso has bounced back from poor qualifying many times this season with strong starts and impressive long-run pace in the races, he is not convinced about his chances of doing so in Korea.
"We need to see what base everybody has," he said. "I think also in terms of degradation we need to see. There are some cars behind us that are a threat, like [Mark] Webber.
"There is Sauber that, from the time we put the 2012 Pirelli tyres on, they were out of Q1 and now they are both in Q3. So there was a big switch and a big penalty for Ferrari and Lotus.
"We need to see tomorrow. We can be on the podium or we can be out of the points, depending how the pace is in the race.
"We need to prepare carefully for the race as it is not straightforward that Ferrari will improve, that we will have better degradation and we will pass people. It is not so clear this weekend and we need to work very hard."
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