Canterbury district commander Superintendent Tony Hill was "disappointed" by the number of fires lit since the ban was put in place at noon on Wednesday.
Hill said arrests are likely as police monitor the region for new fires and investigate several suspicious blazes.
Fire and Emergency NZ introduced the ban in Marlborough, Canterbury and South Canterbury. It includes fireworks and people should avoid using gas cookers outside.
"Police will be investigating any suspicious fires and may prosecute those responsible.
"The fire ban is in place to reduce the risk of wildfires, which can be fanned further and bigger with significant windy conditions forecasted for several days."
The ban, which has been extended till Monday, covers the whole of Canterbury and South Canterbury from the boundary with Marlborough (north of Kaikoura) to the Waitaki River.
"Do not light outdoor fires for any reason. The fire ban also includes fireworks, and police advise people to avoid lighting any fires or using gas cookers outside," Hill said.
Firefighters dealt with several large vegetation blazes which caused extensive damage and property loss this week. The worst was at Kaikoura, where five homes were destroyed.
The strong winds, high temperatures and low humidity helped the fires spread and created difficult conditions for fire crews.
Hill urged anyone who sees a fire being lit when it should not be to call 111 immediately.
