Just 48 hours after an RNZ correspondent posed a payphone paradox: "Why do thousands of them exist when nobody uses them?", Spark has revealed plans to phase out its phone booth calling and free Wi-Fi services.

The cull will start in June, with around 180 booths switched off on Auckland's North Shore and east, and Wellington's south, over the first year of the programme.

The telco has around 2000 phone booths nationwide, inherited when it split from the Post Office in the 1980s.

In 2013, around 750 phone boxes got a makeover so they do double-duty and offer Wi-Fi, but even that has tailed off with the growth of free Wi-Fi and more generous mobile data deals.

"Call volumes on the fixed-line phone booth network have declined by nearly 70 per cent over the last four years, and approximately 90 per cent of them are being used for an average of less than three minutes per day," Spark product director Tessa Tierney said.

"The use of our Wi-Fi hot-spotting has followed a similar downward trajectory."

The phone booth switch-off will track the broader switching-off of copper line phone service - which will impact just under 500,000 households still on the older technology (a process that has seen the Commerce Commission issue switchover guidelines).

Tierney says some phone booths in high foot traffic areas could be repurposed.

One option is to turn some phone boxes into "wayfinders", which use digital signals or simple visual signs to help people find their way around.

Phone booths could also be refashioned to house "environmental sensors or localised news and content", Tierney says.

For phone boxes that don't get a cyber makeover, their sites will revert to public ownership.

"They are generally placed on the road reserve and under the Telecommunications Act we have the right to place our equipment on this land. When a phone booth is decommissioned, we will relinquish the site," a Spark spokeswoman told the Herald.

In the UK, BT has introduced an "Adopt a Kiosk" programme that has seen heart defibrillators installed in some of its disused phone boxes.

Across the Tasman, Telstra said last August that all of its 15,000 payphones would be converted to offer free calling as a community service.

That option is off the table here, with the copper line service that feeds phone booths being switched off.