The tool, developed by University of Canterbury PhD student Karyn Carson, has taken two-and-a-half years to perfect.

It works like a simple 15-minute computer game and can be operated by a five-year-old without adult supervision.

It features four tasks on rhyming, identifying the first sound in a word and recognising letters and letter sounds. More complicated tasks can be added to suit children aged between five-and-a-half and six.

The tool has been designed to assess a child's phonological awareness and produce data a teacher can use to develop tailormade reading programmes.

Phonological awareness is the ability to identify and use the sounds in spoken language. Children need phonological awareness to read.

"In the past, a child may have sat down with his teacher and been assessed using a formal paper-based test, which can be time consuming for both teacher and child," says Ms Carson, a former speech-language therapist and New Zealand Top Achiever Doctoral Scholarship recipient.

Ms Carson's tool also identifies children who are likely to struggle with reading a year down the track. Preliminary tests show her tool is between 92 to 94 percent accurate in assessing a child's reading ability at six years old.

"This tool not only frees up teacher time, it also means five-year-olds - including those who may experience reading difficulties - are more likely to get tested in this crucial area of reading development.

"To me, that's one of the most exciting outcomes of my work," she says.