The number of children seeking sex-changes has hit a record high.

It is expected by the end of 2018, 300 children will have been referred for transgender treatment this calendar year in Melbourne alone.

It comes after 253 youngsters were seen by the Gender Service at the Royal Children's Hospital in Melbourne in 2017, ABC News reported.

It is expected 300 children will be referred for transgender treatment by the end of this year at the Gender Service at the Royal Children's Hospital in Melbourne (stock image)

Over the past decade, there has been a huge increase in the number of children being referred to the service.

Only two patients were seen by the service in 2008, and just three more in the five years before that.

Children and teenagers no longer need permission from a court to start hormone therapy following a landmark ruling made by the Family Court last year.

Gender Service director Michelle Telfer told the ABC the figures were 'interesting' because the increase has not just occurred at the hospital, it is 'very similar and mirrored really by other services internationally'.

The Gender Service at the Royal Children's Hospital in Melbourne (pictured) has seen a huge increase in the number of children being referred to its service in the past decade

NUMBER OF GENDER SERVICE REFERRALS 2003 - 1 2004 - 0 2005 - 1 2006 - 0 2007 - 1 2008 - 2 2009 - 6 2010 - 7 2011 - 8 2012 - 18 2013 - 40 2014 - 104 2015 - 170 2016 - 226 2017 - 253 Source: Royal Children's Hospital, Melbourne Advertisement

A total of more than 1,000 children will have been referred to the service by year's end.

The sharp increase in the number of patients saw wait times blow out to 14 months but they are now just four months after nurse consultants and junior doctors started carrying out initial assessments.

But paediatric and psychological approval is still needed before puberty blockers and hormone therapy can start.

The $5,000-a-year treatment cost for each patient is paid for by Victorian taxpayers.

The Pharmaceutical Benefits Scheme covers hormones but not puberty blockers.

Gender-reassignment surgery is not available at the hospital.