More than 160 flights to and from Tokyo's Haneda airport were disrupted Thursday after a computer glitch hit a new air radar system hours after it was installed, the transport ministry said.

The malfunction slowed data transmissions from 10:37 am (0137 GMT) until shortly before noon, and 22 flights were cancelled while another 140 flights were still delayed as of 5:00 pm, an official said.

"The government is currently investigating the cause of the system trouble, including whether it was due to the new system being installed," he said. "A few more flights may yet be affected today."

The new system was installed early Thursday at Haneda where a fourth runway is due to be completed in October.

Haneda now handles domestic flights and routes to and from , Seoul and , while the outlying Narita airport serves other international routes and connecting domestic trips.

Japan's government plans to upgrade Haneda into a 24-hour international hub.