Protesters have barricaded themselves inside university buildings in recent days, and now risk being tear-gassed or shot with rubber bullets if they flee.
The FCO said protests across the territory have resulted in “significant violence” in recent days.
Travellers are advised to avoid areas where protestors are gathered, take extra care when moving around university campuses, and follow the advice of the authorities.
“The situation around protests and public gatherings can change quickly, with the potential for violence, especially during unauthorised protests,” said the FCO.
“If you’re in an area where demonstrations are taking place, you should remain vigilant, follow the advice of local authorities and move away quickly to a safe place.
“During the week of 17 November, there have been exchanges between police and protesters at the Polytechnic University, including the use of petrol bombs, tear gas and rubber bullets.
“The situation is volatile and visitors to the area around the university in Hung Hom should exercise caution and be alert to the changing situation.
“Previous demonstrations have led to sections of the city being closed off and temporary suspension of public transport without warning.
“Some Mass Transit Railway metro stations, including in major tourist areas, have been closed due to damage caused by protests.”