Eurostar is among rail services set to be disputed in Belgium next week.
The Foreign and Commonwealth Office (FCO) warned of a large scale political demonstration on Wednesday followed by a 24-hour train strike on Friday.
These “may cause disruption to public services and transport, including Eurostar. Be vigilant and check with your travel company and local media for more information,” the FCO added.
Belgian Railways said Eurostar trains from London to Brussels will only operate to Lille on October 9 on a reduced timetable with some cancellations.
The 7.38pm departure from St Pancras on October 8 has also been cancelled.
The majority of Thalys trains between Brussels and Paris will not run next Friday although TGV services between the two countries are expected to operate normally.