One of five nominees, Semenič won the Grum Prize best original play for "seven cooks, four soldiers and three sophias", a tribute to Sophia Magdalena Scholl, a member of the German anti-Nazi resistance movement, Russian revolutionary Sophia Perovskaya and French mathematician Maria Sophie Germain.
The play condemns war, conformism and elimination of people whose actions make them stand out above average. Despite the difficult theme, the play is written in a light, humorous and flowing way, offering a challenge to perform, the award jury said.
Semenič, who already won the Grum Prize in 2009, said that her play was about "the society we live in that is full of bureaucratic and other nonsense, and about individuals who want to overcome the passivity but fail". The pay is to be put on at Ljubljana Mestni Theatre in September.
A production based on Semenič's play "1981" about the last generation of Tito's Organisation of Pioneers meanwhile won the Šeligo Prize for best production of the 45th Week of Slovenian Drama, selected among eight shows in the running for the award.
Put on by the Academy for Theatre, Radio, Film and Television (AGRFT) and Glej Theatre and directed by Nina Rajić Kranjac, the play is set in a small town in a timespan of three decades to juxtapose the moral emptiness of today's consumerist world with the ideologised past.
Katja Markič took best up-an-coming playwright award for "Migratory Birds", which sees three antagonists discuss in hushed voices relationships, the almost nomadic nature of man migrating between memories, thoughts, speech, silence and backwards.
Accepting the award, Markič said she was greatly honoured. "It means I have been in a way initiated among bigger playwrights."
The Grün-Filipič Prize for achievements in dramaturgy in the past ten years, which Prešeren Theatre as the organiser of the festival gives out once in every two years, went to Vasja Predan, a critic, columnist and theatrologist, for his sensitive observations on the Slovenian theatre.
Out of 16 productions on show in the competition, accompanying and international programme at the Kranj theatre in the past twelve days, the audience rated the best Evald Flisar's "Take Me in Your Hands", directed by Dipika Roy and produced by Banyan Tree Productions from Bombay, India.
The festival, which attracted 2,200 visitors, also featured three productions of "Comedy about the End of the World", a play that won Fisar the Grum Prize at the festival two years ago. Aside from the home ensemble, the play was also put on by Yatrik Theatre from New Delhi and Austria's Theater im Keller.
Addressing the award ceremony, Culture Minister Julijana Bizjak Mlakar described culture as one of the most successful domains in Slovenia. It contributes to the promotion, development of Slovenian language and national identity, she said.