The arrests come as cities around the world heighten security measures ahead of large-scale New Year celebrations.
The arrests in Brussels were made during raids in suburbs including Molenbeek, which was used as a base by the November 13 Paris attackers.
Brussels’ main fireworks display has been cancelled over the feared plot.
None of the six people arrested on December 31 have been identified. Two people arrested in Brussels earlier this week, named as 30-year-old Said S and 27-year-old Mohammed K, have been charged with threatening to carry out a terrorist attack.
According to Brussels police, the apparent plots to target New Year celebrations are not related to the network behind the Paris attacks.
Security is being stepped up in major European cities ahead of New Year celebrations, with officials wary of possible terror plots.
New Year fireworks and festivities have been cancelled in Brussels and extra measures are being put in place in other cities, including Paris, London, Berlin and Moscow.
Meanwhile in Turkey, security services say they have thwarted a major plot to attack celebrations in Ankara.
Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…