A children's transgender support service that has experienced surging demand has received a cash boost from the Victorian government to reduce its lengthy waiting list.

The waiting list for the gender dysphoria clinic at the Royal Children's Hospital has blown out to more than 14 months.

The Andrews government has announced it will spend an extra $6 million over four years to reduce the waiting time.

The government reported the number of referrals to the service rose from single figures by 2007 to 104 last year.

The service expects new referrals could exceed 150 this year.