The New Zealand Air Line Pilots Association is concerned unmanned air traffic control towers are unsafe for travellers.
Four times in September, Napier Airport's control tower was left unattended due to staff shortages.
The Pilots Association says it’s not ideal.
"That's a concern for the airline operators, the pilots operating in and out and the travelling public." ALPA’s President Tim Robinson told 1 NEWS.
On September 12, the tower was left unmanned for 5 hours and 20 minutes and on September 16, there was no one on shift for six hours and 30 minutes.
Two days in a row on September 18 and 19 there was no one in the tower for seven hours and 20 minutes.
The subsequent delays frustrated locals with Government Minister and Napier MP Stuart Nash even venting on social media.
Airways NZ runs Napier's control tower and it employs five controllers who work solo shifts. It says that's usually sufficient but any unexpected absences at short notice are difficult to cover.
In these cases, air traffic is directed from Christchurch.
The Civil Aviation Authority requires approved contingency procedures for when control towers aren't staffed and appropriate safety measures to be put in place. With those in place, it says it has "no concerns at this time" regarding the matter.
Mr Robinson says they've heard of similar staff shortages in the Raglan area.
"It gives us an indication that perhaps the manning levels aren't what they should be and it needs to be rectified.”
Remote digital control towers using high definition cameras are currently being assessed with the technology already used at airports overseas in London and Singapore.
Mr Robinson says they aren’t against the technology.
“We embrace the technology, we think it's got a future in New Zealand… it's just got to be implemented safely.”
Airways NZ plans to have the first digital tower online in Invercargil in 2020.
SHARE ME