Police are asking the public to be vigilant after a "handful" of petrol thefts in the Whanganui East area.
"If they're driving through the area and there people hanging around cars or they see them walking up driveways or walking with a petrol can at 11 o'clock, 12 o'clock atnight, call 111," Senior Sergeant Andrew McDonald said.
"We've had an increase of suspicious activity in and around the Whanganui East area, particularly around Whanganui Girls' College."
CCTV footage in the area showed two occasions - one on June 7 and one on July 6 - where a male Caucasian entered the hostel grounds and siphoned or attempted to siphon fuel out of cars.
Mr McDonald said petrol thefts used to be common, but modern cars often had anti-theft technology to prevent fuel being siphoned.
He said thieves would probably target cars without locks on the petrol flap, or vehicles that were unlocked.
He believed the two thefts caught on video were linked.
A witness to the June 7 incident described the offender as male Caucasian in his early 20s, about 5'10" tall (175-180 cm), skinny build, shaved hair and wearing a black hoodie and black sports pants.
