Actress Melissa Joan Hart has been targeted by abusive Internet 'trolls' over her political preference for presidential candidate Mitt Romney.

The Sabrina the Teenage Witch star received a string of offensive comments on her page shortly after Barack Obama was re-elected as U.S. President on Tuesday (06Nov12).

The actress retweeted some of the abuse she received, including a message branding her "a fat, unbankable, untalented, uneducated, neo-con, bad mum, child star from the 80s" and another reading, "hey Sabrina, f**k you".

Hart hit back at her attackers, insisting she was disgusted by the messages and adding, "Wow it's incredible how tasteless and disgusting some of you can be when u r (sic) hiding behind your keyboard. Don't like me, don't follow me!!!... Such a lovely tweet to read while up feeding my 7 week old son!... Makes me sad that my 3 boys will someday see all this hate people are spewing. Ive (sic) never said anything hateful on twitter to deserve this!"