Protests over what demonstrators termed excessive pay and housing allowances for parliamentarians started on Monday.
They expanded into riots on Thursday after one person - a motorcycle rideshare driver - was killed in police action at a protest site.
The homes of some political party members and state installations were ransacked or set ablaze.
Prabowo, speaking on Sunday at a news conference at the Presidential Palace and flanked by the leaders of various political parties, said he had ordered the military and police to take stern action against rioters and looters, warning that some of the actions were indicative of "terrorism" and "treason".
"Leaders in parliament have conveyed that they will revoke a number of parliament policies, including the size of allowances for members of parliament and a moratorium on overseas work trips," Prabowo said.
"To the police and the military, I have ordered them to take action as firm as possible against the destruction of public facilities, looting at homes of individuals and economic centres, according to the laws."
The protests are the biggest test yet for Prabowo's almost one-year-old government, which has faced little or no political opposition since taking power in October.
Subianto cancelled a planned trip to China as the protests spread further outside the capital Jakarta, with several regional parliament buildings set ablaze.
Prabowo had been due to attend a Victory Day parade in China on Wednesday to mark the 80th anniversary of the end of World War Two, following Japan's formal surrender.
"The president wants to continue monitoring (the situation in Indonesia) directly ... and seek the best solutions," presidential spokesperson Prasetyo Hadi said in a video statement.
"Therefore, the president apologises to the Chinese government that he could not attend."
Another consideration in cancelling the trip was a United Nations General Assembly session in September, Prasetyo said.
In light of the protest, short-video app TikTok, owned by China's ByteDance, said on Saturday it had suspended its live feature in Indonesia for a few days.
Jakarta had this week summoned representatives of social media platforms, including Meta Platforms Inc and TikTok, and told them to boost content moderation because disinformation had spread online.
The government said such disinformation had spurred protests against it.
Protesters caused fires at regional parliament buildings in three provinces - West Nusa Tenggara, Pekalongan city in Central Java and Cirebon city in West Java - local media reported.
Demonstrations also occurred on the holiday island of Bali, where tear gas was used against protesters.
