"There's a trend of on-roof tagging at the moment, which makes a lot more safety issues [when it comes to removal]," D Tag graffiti-buster Pomare Pou said.
"There's [also] a lot of the bombing-type style - normally it's the scribbling. Now they are covering wide areas and it's really time-consuming to remove."
There was a whole raft of reasons as to why people tagged, including lack of respect for people's property and lack of a wider understanding of the effect tagging had on the community, Mr Davis said.
He believed the problem needed to be tackled by the community as a whole, including whanau.
"[For example] are we keeping an eye on our young people - as parents, do we know where our kids are?"
In an attempt to catch taggers, D Tag, the council, Northpower and police are using the Stop Tags database - which allows police to have instant access to photos and information about tags around the district.
"At this stage we are very committed to - if we can - identifying the tagger and putting the information to police," WDC group manager district living Paul Dell said. "We are focused on our top 10 [taggers], and trying our best to curtail that.
"We continue to see high-density tagging with marker pens as an issue, particularly in the inner-city area, Regent, Kensington, Whau Valley (Kamo Bypass), Otangarei and Tikipunga."
That tagging was being attributed to the same group of youths who frequented those areas, Mr Dell said. "Commercial buildings are the predominant target, followed by private fences and council assets, such as bus shelters, parks and reserves, road barriers and signs, and public facilities."
WDC spokeswoman Ann Midson said it was difficult to put an exact figure on the cost of removing graffiti because tagging fell under the umbrella of vandalism, which included all forms of destruction of property.
The council spent $500,000 a year on measures to address vandalism, which included the cost of making things vandal-proof, with prevention techniques such as City Safe and security cameras, as well as the cost of cleaning up graffiti and repairing property, she said.
Other funding came from the Ministry of Justice with the likes of the Supervised Work Programme, under which youths helped clean up tags as part of community service. The programme had relationships with the Lion's Den Ministries and Te Ora Hou Whai Ake youth programme.