Scotland Yard originally held the 53-year-old on Monday for the alleged possession of explosives.
But on Tuesday he was further arrested on suspicion of the commission, preparation or instigation of an act of terrorism.
Specialist officers continued to search the property where the man was detained.
“There is a cordon in place,” the Met Police said in statement.
“The risk to people in nearby properties has been assessed and it hasn’t been deemed necessary to evacuate addresses in the surrounding area.