Serious concerns are being raised about an emergency text service for deaf people, less than a week after it started.
Police Minister Judith Collins introduced the 111 text service on Friday.
It is designed to give deaf and hearing-impaired people improved access to emergency services.
More than 600 people have registered and that figure is expected to rise dramatically in the next few weeks.
But some people within the deaf sector say the system is flawed.
Issues raised include delays occurring as the text message is received at a police communications centre and then forwarded to the appropriate emergency service.
Another is the event of a network failure and the text not being received immediately or not received at all.
National Foundation for the Deaf chief executive Louise Carroll yesterday praised the police for introducing the system, but said the issues were serious and needed to be addressed.
"We all know that text messages can go haywire so appropriate resources need to go into making sure that a message will always be received in an emergency."
Mrs Carroll said she had written to the police commissioner and the minister outlining the issues and askingfor a back-up information technology system.
A mix of responses had been received by deaf and hearing-impaired people, she said, many of whom were happy that there was a service for their needs but also disappointed that the system was not a guaranteed one.
"It's not ideal, but that's why the letter to police has been made," she said. " People with hearing impairment really do need a voice - it's pretty isolating."
Police yesterday said they had advised members of the deaf community they worked with through the development of the service that there was a possibility of network delays, and this was made clear from the start.
The national manager of police communications centres, Superintendent Andy McGregor, yesterday said: "We've explained this at meetings around the country. This information also forms part of the terms and conditions that participants agree when they register for the 111 text service."
Audiologist Catherine Camp said she had concerns about possible delays, but was worried by the fact that many f people could not use it, as they did not have mobile phones.
"A lot of my patients are elderly and are not going to have a mobile phone or even know how to text. It's great for young people, but I don't think it's helping many others."
Ms Camp said network failures were a big problem and something that needed to be looked at.
One of her patients, Rose Hardy, said she used her mobile phone only "as a normal phone".
The 76-year-old, who wears hearing aids, doubted she would use the system: "You're going to have to be a good texter won't you? And I'd be too nervous to text in a panic. Imagine if you made a mistake?"
WHAT THEY SAY
Deaf 111 Text Service, police said:
Friday Oct 15: "Police will receive and respond to all emergency texts on behalf of the New Zealand Fire Service and ambulance services. If it's a medical or fire emergency, police will pass details electronically to the Fire Service or ambulance communications centres for dispatch."
Yesterday: "We have advised the deaf community about the possibility of network delays and told them that if they don't get a response from police within two minutes of sending their first text, they should contact 111 another way."