"Over the last few years this event has seen high levels of anti-social behaviour, crime and disorder. This year we have strong reason to believe that peaceful protest is the last thing on the minds of many of the people who will come along," Chief Superintendent Pippa Mills was quoted as saying in a statement posted on the MPS website.
The demonstration is an annual event, which has been held in the United Kingdom since 2012.
Activists have already called on their followers to be watchful of police actions during the rally.
"The police are not your friends, this goes for police liaison officers too, they're simply a 'friendly face' who collect intelligence. Keep an eye out for your comrades and police tactics that will limit movement, the hive mind should stay vigilant," the group wrote on their Facebook page.
In 2014, at least 10 people were detained for vandalism of public buildings and violence toward police officers.
This year, police have been granted the right to force protesters to remove their masks in locations where they think criminal offenses are likely to happen.
