A ban on alcohol came into force around Tokyo's tourist hotspot Shibuya on Friday in an attempt to discourage raucous Halloween gatherings a year after a deadly crowd crush in South Korea.

Nearly 160 people were crushed to death in a narrow alleyway in Seoul on 29 October last year after tens of thousands of people poured into the Itaewon neighborhood to celebrate Halloween.

In Tokyo, tens of thousands of people, Japanese and foreign alike, have thronged the narrow streets around Shibuya in past years, many dressed up in Instagram-ready zombie costumes.

The crowds have slowed down emergency services attempting to reach people in need.

"We're extremely concerned accidents similar to the fatal case in Itaewon in Seoul last October could happen anytime," the district's mayor Ken Hasebe said this month.

Ahead of this weekend, a video released by authorities in Japanese and English focused also on the annoyances caused to locals such as vandalism, litter, and noise.

"This Halloween night everyone should stay away from Shibuya. Some people live in Shibuya," the video message said. 

"Violence. Drinking on the street. Smoking on the street. Traffic violation. You can't choose how your actions will affect others."

Billboards have been put up and a famous statue of Hachiko the faithful dog that is a popular meeting place outside Shibuya Station was also set to be covered up with a temporary enclosure.

Some residents welcomed the restrictions.

"I think it's a fair decision because I find that these celebrations have become more and more excessive in recent years," said Ryosuke Yamazaki, 35.

"If this were to get even worse than before there could be a disaster or even something on the order of what happened in South Korea," he told AFP.

Kosuke Kimura, 21, called the restrictions "entirely appropriate". 

But US tourist Laura Williamee, 35, said it was "very disappointing". 

"I booked this flight a while ago and I was looking forward to being in Shibuya for Halloween… (but) I understand it can get dangerous," she told AFP.

"I think they do have the right idea and they want to protect the people and all the tourists and stuff, so I do understand. I'm not upset about it. It is just disappointing."