"At 18:30 we are going to PA on Bankova [street]!" Sakvarelidze wrote on his Facebook account.
The activist also said that Saakashvili had contacted him and confirmed that he was in Warsaw.
Former Georgian president, ex-governor of Ukraine's Odessa region and current opposition leader, Mikheil Saakashvili was deported from Ukraine on Monday on board a charter flight bound to Warsaw, a spokesman for Ukraine's border service said earlier in the day.
"This person was on Ukrainian territory illegally and therefore, in compliance with all legal procedures, he was returned to the country from where he arrived," the spokesperson wrote in a post on Facebook.