The incident was reported when a 16-year-old girl went home and told her mum that she and a friend saw the man watching porn on a library computer. The school kids then decided to film him on one of their phone to prove it happened.
The girl's mum, who only wants to be known as Margot, reported the incident to Manly Library.
'They were sitting at a table and a guy behind them was watching fairly explicit porn,' Margot told the Sydney Morning Herald.
'He was in close proximity to them and a woman sitting next to him moved.'
The council that runs Manly Library has now been forced to install internet search filters across its library network.
'We acted as soon as this incident was brought to our attention and immediately installed filters to block access to this type of material,' said Northern Beached mayor Michael Regan.
