The hackers, wearing Guy Fawkes masks, faced off with dozens of riot police outside the House of Representatives in suburban Quezon city north of Manila, blocking the road and bringing traffic to a standstill for around an hour.
"We are here today to press for a new system of government," said one of the leaders who did not give his name.
"We are everyone and anyone. We will not go away and we will continue with our activities."
Last week, the group launched simultaneous cyber attacks that temporarily paralysed more than 30 government websites.
They defaced the sites with messages calling on the public to support their cause.
The government says it will prosecute members of the group, but has conceded it is yet to determine their identities.
Global activist network Anonymous have carried out a number of attacks and threats in recent weeks.
The Indonesia group claimed last week it had defaced more than 170 Australian websites while the Singapore government boosted its defences after a threat.
President Benigno Aquino has been hit by the scandal after one of the senators named in the case alleged that his office had misused funds.
Last week, with public anger growing, Aquino went on national television to publicly declare that he was "not a thief" in an attempt to head off the growing crisis that threatens to derail his political agenda.
