Ressa was formally arrested on Wednesday, JJ Disini, one of his lawyers, told CNN, and added that he would go to the night court in Pasay City to post bail.
Earlier in the day, he served a warrant of arrest by officials of the National Bureau of Investigation (NBI) of the Philippines, reported by Rappler.
Rappler said that authorities have tried to stop some of its publishers from filing Ressa's trials on Wednesday, and an official who refused to give his name to the reporter threatened "Follow me too."
CNN attempted to reach the Philippines with the NBI by telephone but the agency did not get it.
Rappler's extensive report of President Rodrigo Duterte's brutal war in drugs has received praise from human rights advocates, but the site and its publishers are a target of supporters of Duterte administration
Prosecutors filed five five tax-exempt cases against Ressa and Rappler last year. Some of the charges said the company failed to declare about $ 3 million in 2015 on tax returns from an Omidyar Network investment, a fund created by the eBay founder and pilantropist Pierre Omidyar.
Duterte's office denied that he had been involved in persecution against Rappler, but the President was formerly sparred with company employees, personally banned Ressa and reporter Pia Ranada from the Malacanang Palace, his official residence, in their conquest of his administration.
Ressa worked for CNN before the start of Rappler, an online news site that has since become an indispensable source of information for readers in the Philippines and internationally.
CNN's Karen Smith report contributed.