Leading educators, academics and teachers are sounding the alarm over the impact excessive screen time is having on Australian children's reading, writing and ability to concentrate in school.

A Four Corners investigation has found there are growing fears among education experts that screen time is contributing to a generation of skim readers with poor literacy, who may struggle to gain employment later in life as low-skilled jobs disappear.

By the age of 12 or 13, up to 30 per cent of Australian children's waking hours are spent in front of a screen, according to the Longitudinal Study of Australian Children.

Robyn Ewing, a Professor of Teacher Education at the University of Sydney, said this was having a tangible impact on vocabulary and literacy.

"Children who have been sat in front of a screen from a very early age start school with thousands and thousands of words less, vocabulary-wise, than those who have been meaningfully communicated with," Professor Ewing said. READ ARTICLE>