The city will find out today how much it will have to pay in fines for failing to comply with a court order for a timely release of protesters arrested for demonstrating during the Republican National Convention.

Judge John Cataldo of Manhattan Criminal Court last week ordered the city to release hundreds of protesters who were detained for more than a day, but the city said it couldn’t make the judge’s deadline because the large number of protesters arrested overwhelmed it. The city stands to be fined as much as $470,000.

Speaking to reporters at the opening of Fashion Week in Bryant Park yesterday, Mayor Bloomberg gave his most exhaustive explanation to date as to why some demonstrators were held in an old bus depot at Pier 57 for longer than the 24 hours the law allows: The Department of Corrections was overwhelmed.

“Tuesday was the day when we had about 1,200 arrests,” he told reporters. “And that is because there were messages on the Web that said ‘Let’s come and let’s hurt New York City.’ People came here and they wanted to get arrested and we accommodated them and they did.”

Mr. Bloomberg said the Manhattan court system typically handles 200 to 300 cases a day and having six times that many people suddenly in line for the docket overwhelmed the system. “We just couldn’t process people as fast as we would have liked,” Mr. Bloomberg said.

The mayor said the arrests were clearly warranted given that the Manhattan district attorney’s office has chosen to prosecute all but three of the arrests during the convention. “Did we arrest the right people?” Mr. Bloomberg asked. “The answer is clearly yes.”

Even with the support of the district attorney, the Bloomberg administration is bracing for dozens of lawsuits that will likely be filed against the city as a result of the detention and the treatment of protesters more generally. The National Lawyers Guild, for example, has made clear it intends to pursue lawsuits and perhaps a class-action suit against the city.

As he awaited the verdict yesterday, Mr. Bloomberg tried to put the best gloss on the situation, focusing on how generally peaceful the demonstrations were. “A lot of people thought what you would see is what you saw in Seattle…or the disaster that took place in Chicago when police were kicking people.”

He said the only person who was seriously hurt during the four-day convention was a police officer.

“In terms of the judge, we will go and make our case,” he said. “We believe that we acted appropriately and, given the situation and constraints, we did as the law requires. Hopefully, we learn from this and keep improving our procedures all the time.”