The proposed tax reform was originally meant to raise about $6 billion, equivalent to 2% of gross domestic product (GDP). However, earlier on Wednesday finance official Juan Alberto Londono said the government could lower the targeted sum to between 18 trillion and 20 trillion pesos ($4.8 billion to $5.4 billion) as it looks to build consensus among lawmakers.
Wednesday's protest is the most recent in a series of marches which began near the end of 2019 against the social and economic policies of President Ivan Duque, who leaves office next year.
The government is proposing a suite of new or expanded taxes on individuals and businesses, as well as reducing or eliminating many tax exemptions, including on product sales.
The reform is crucial for Colombia to keep its investment grade debt rating, according to the government.