Blaine Higgs says the added cost is unfortunate, but the government has a responsibility to ensure enforcement when there is unlawful activity.
An anti-shale gas protest near Rexton turned violent in October when police enforced an injunction to halt the blockade of a compound used by SWN Resources to store exploration equipment.
Forty people were arrested and six police vehicles burned.
Public Safety Minister Bruce Northrup is defending the police action, saying officers discovered weapons during the protest and their response was appropriate.
SWN Resources has since been granted another injunction that provides a buffer zone around its equipment in an effort to complete its seismic testing.