A rogue monkey holed up at a Tokyo train station for more than two hours this morning before giving dozens of net-wielding police officers the slip among crowds of excited children and passersby.

"It's a monkey - it's not like it did anything bad," a police spokesman said, adding that the animal was still on the loose.

The monkey was spotted hopping around by the automatic ticket gates at a train line in Shibuya Station in central Tokyo at about 2 a.m. (Malta time).

It then ran downstairs to the entrance to another line, climbed up and down a pillar and ran around the ticketing machines before taking refuge on top of a train information board for two hours, a spokesman for railway operator Tokyu Corp said.

Television footage showed the 60-cm-tall brown monkey sitting calmly on top of the board, blinking and looking down at the crowd.

Around 30 police officers and other officials cleared the area and surrounded the animal with green netting, but at noon it jumped off the information board and escaped through the crowd.

"I've heard of mice before, but nothing like this," said Jiro Umegaki, a spokesman for Tokyo Metro Co Ltd.