Communications into and out of Honolulu International Airport were cut off this afternoon for about two hours, requiring airlines to manually check in passengers, the state Department of Transportation said.

Officials said Hawaiian Telcom technical difficulties caused the telephone failure starting about 1:30 p.m. By 3:53 p.m., communications had been restored.

Flights were still landing and departing with air traffic control functions still operating normally, officials said. Emergency phone lines remained operational.

"It did affect all the airline carriers, because they were unable to electronically process and check in customers," said DOT spokeswoman Tammy Mori. "They had to do it all manually. So for about two hours, it did affect all airline carriers. ... It kind of slowed down the process altogether."

The DOT said passengers should allow for more time at the airport today as a result of the check-in problems.

Officials said no flights at the overseas terminal were affected, but Hawaiian Airlines flights did see a backup. Eight overseas Hawaiian flights out of 12 total this afternoon were delayed, but there were no cancellations, officials said.

Mesa Air had three inter-island flights delayed, according to officials.

Hawaiian Telcom officials could not immediately be reached for comment. A message was left with the phone provider.

"I know the area that was affected included the airport area and the surrounding area. I'm not sure what the cause was," Mori said.

The communication problems follow Friday's islandwide electrical failure, which also brought a halt to some airline departures and caused a huge backup of passengers trying to get through a security screening bottleneck.

Reach William Cole at wcole@honoluluadvertiser.com or 525-5459.