The cost covers the works' design, manufacture, installation, provision of power supply, engineering for the foundation, and reinstatement of the pavement.
The work included laser cutting, hot-dip galvanising, painting, LED and Opal diffuser illumination, toughened glass and translucent digital prints.
Of the total cost, $6000 paid for the artists' fees of six prints, two in each box. The prints were $1000 each.
A member of the public contacted council recently asking for the total cost of the artwork.
"At the public meeting . . . I raised the issue about cost," they said in an email to chief financial officer Jo Devine.
"The figure I quoted on the day was $120k, and this was dismissed by every councillor in the room, Anita Baker the mayor, and yourself," they said.
"Anita said it was more likely to be $12k per light box. As you can [see] from your investigation my figure of $120k is far closer to the real number."
The resident said the community was in a time of "great change" with the pandemic and huge increases in the cost of living.
"When times are tough, everyone has to tighten the purse strings," they said.
"If people are struggling to put food on the table you don't expect them to buy Moet and caviar. You decide on the needs and the wants.
"Spending $123,714 is definitely a want and not a need."
They said the spending was mentioned as part of the cultural budget.
"Every person in the room, no matter was culture or ethnicity they came from had a problem with the spending of this money," they claimed, describing the spending as "totally unnecessary and very much a luxury that should not have been spent in the current economic times".
"There is no point having something that adds to the vibrancy and vitality of the city when people are living in cars and others are living off food banks."
Council announced the installation of the boxes in July, saying they would showcase local artists and their work.
The boxes were installed in the spine of Porirua's CBD, Te Manawa, running from Hagley St to Ferry Pl.
The first installation was by Ngāti Toa's Kohai Grace, featuring her weaving, modelled by her Hongoeka whānau, and photographed by her brother.
"This wonderful opportunity has provided a new way for me to share and continue the mātauranga Māori of this ancient art form that has a rich whakapapa, interweaving past, present and future," she said at the time.
Mayor Anita Baker said a lot of work had been done to make the centre of the city "colourful and attractive".
"The way that Ferry Pl has been opened up to link with the railway station, the stunning artwork on the backs of the buildings, now the lightboxes, which will look great at night - it all adds to making Te Manawa a place residents and visitors can enjoy," she said when the boxes were unveiled.
The three lightboxes will be changed with new artists' work every four months.
Council's general manager of community and partnerships Reuben Friend told NZME the city centre revitalisation budget was established in 2012.
"This has funded all the public space improvements undertaken since then and includes other improvements such as wayfinding and lighting," he said.
"The lightboxes are positive for Porirua on a number of different fronts – they brighten the city centre, making it well-lit in the evenings and safer for our residents and visitors; reflect our cultural values, including (in some artwork) of our mana whenua Ngāti Toa; and serve to support and highlight the work of local artists, showing off the cultural identity that we want to foster where possible in Porirua."