A Christian kids entertainer who was fired from her Canberra job for saying she would vote 'no' in the same-sex marriage survey has hit back, saying she is "not afraid to stand up for my beliefs" and should not have lost her job.

The 18-year-old, who only identified herself as Madeline, was hired as a contractor and worked just two shifts for Capital Kids Parties in Canberra before she was "let go" on Sunday.

Madeline had updated her Facebook profile picture two weeks ago with a filter designed by the Coalition of Marriage that said "It's OK to VOTE NO".

Capital Kids Parties' owner, Madlin Sims, wrote her a private Facebook message on Sunday saying that "homophobic views being made public are detrimental to the business and don't align with my personal values or morals as the owner of the business".