Wellington Free Ambulance (WFA) workers are considering strike action after negotiations broke down between union members and the employer.

FIRST Union members were offered an "insulting" 1.5 per cent pay increase during negotiations, which National Ambulance organiser Faye McCann said was "an effective pay cut" as the Consumer Price Index is up to 7.3 per cent.

"Our members believe that WFA are waiting until their upcoming fundraising drive begins, but they are still not confident that any of those donations will find their way to frontline officers."

Wellington Free Ambulance is partially funded by charity through things like Onesie Day, where people are encouraged to wear onesies and donate to the service, but McCann says this model is unsustainable.

"The charity funding model is failing both patients and ambulance officers.

"Our emergency health services require well-trained and experienced ambulance officers, but low pay and difficult conditions mean many people are immediately turned off from the profession."

She said services are underfunded and "teetering on the edge".

"Fixing that starts with keeping people in the job by paying them properly for what is one of the most challenging frontline professions in the country."

McCann said Wellington Free Ambulance members had the right to strike during negotiations and were currently considering their industrial options.

It comes as the firefighters union escalates its strike action over pay and mental health and wellbeing.

Fire and Emergency New Zealand (FENZ) has been given notice today that all New Zealand Professional Firefighters Union members covered by the bargaining will stop work for one hour from 11am to midday on August 19 and for the same time on August 26.

The strike action includes all career fire stations, training centres and 111 fire communications centres.

The negotiations for a collective agreement began in June last year and 13 months later little progress has been made, the NZPFU said.