The Fire Service says it is worried about a trend of deliberately-lit fires in empty Christchurch houses.
Firefighters spent much of the long weekend battling four suspicious blazes at empty properties throughout the city.
Properties in the suburbs of New Brighton, Burwood, and the central city, as well as a garage in Linwood were burning on Saturday and Sunday night.
Christchurch's senior fire risk management officer, Mark Thomas, says there have been about 60 deliberately-lit fires on empty properties this year, and that's a worrying number.
Mr Thomas says the trend is fairly steady, with several suspicious fires every few weeks.
He says there are probably a few groups of people doing the damage, and they may not be known to each other.