The de Blasio administration was surprised that some users of its free, municipal internet hogged the sidewalk kiosks and viewed pornography in public, according to testimony Tuesday before the City Council.

Despite software intended to filter out lewd material on the kiosks’ tablets, users managed to evade the restrictions, said Stanley Shor of the city’s Department of Information Technology and Telecommunications, which oversees the contract with the kiosk vendor, CityBridge.

“They included pornography filters, but apparently people are very clever in getting around filters,” said Shor, the department’s assistant commissioner of franchise administration.

Since the program was announced in 2014, hundreds of defunct pay phones have been converted into LinkNYC kiosks, offering free internet services. De Blasio wants to help close the so-called digital divide that deprives poor people of web access that’s increasingly necessary in the 21st century.

But complaints began to mount about inappropriate use and, in September, the tablets stopped allowing free web browsing amid reports of people viewing lewd material and using the terminals for hours.

“We did not anticipate this, and when it became a problem, we all looked at it and said, nice as it would be to have this available, it was more of a problem than it was worth,” Shor said.

The kiosks continue to offer unfiltered browsing via Wi-Fi on a user’s own device.

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Under the city’s contract with CityBridge, advertising revenue is split with the city. The original goal was to bring in $20 million a year, later amended because of litigation to $17.5 million. The kiosks have generated $18 million.

Councilman Jimmy Vacca (D-Bronx) complained to Shor and LinkNYC’s Jen Hensley that the kiosks are too concentrated in Manhattan — and that the other boroughs are in the “rear end” of the plan.

“Manhattan has much more than the four other boroughs combined,” Vacca said.

Hensley said that tablet web service could return sometime in the future — with stricter filtering.