You could lose your licence due to double demerits this weekend and not know it

Sydney drivers are at extra risk of losing their drivers licences during this public holiday weekend – although they won't find out about it until later this month.

New data - obtained exclusively by 9News under freedom of information laws - reveals at least 1,300 people have exceeded their maximum demerit points for using their mobile phones during double demerit periods over the past year.

Public holidays are disastrous for drivers caught touching their phones because they get hit with 10 points for one offence, pushing many regular licence holders up to or over the 13-point threshold.

READ MORE: Recent changes to mobile speed cameras in NSW under review

P-platers and L-platers automatically lose their licence for any mobile phone offences.

The data released by Transport for NSW shows more than 8,800 drivers have reached the loss of licence threshold for mobile phone offences since July last year.

The vast majority of drivers will be caught by controversial unmarked mobile phone detection cameras, which resemble ubiquitous roadworks equipment or are mounted in gantries and rake in more than $5 million in fine revenue every month.

Others may be caught by NSW Police.

READ MORE: Mobile speed and phone detection cameras are being destroyed by angry drivers

Critics argue these cameras are more about revenue-raising than safety because they don't change driver behaviour, with notification and a fine only arriving in the mail weeks after the offence happened.

The NRMA and NSW Opposition are calling for warning signs to be introduced ahead of the cameras.

As well as demerit points, drivers must pay a $349 fine for mobile phone offences – which rise to $464 if they occur in a school zone.