His poetry has been characterised by Jacques Alvarez-Pereyre as follows:
Totalitarian regimes have the citizens and poets they deserve, those who accept the bayonets upon which order is based and who, by their silence or useless chatter, make themselves the accomplices of those who rule. Peter Horn' is not one of these: he has chosen to be on the side of the oppressed, on the side of the future, of the dream of a multiracial society, in short, on the side of freedom.,
Lionel Abrahams said that his poetry "is overwhelmingly the record of his responses to aspects of the South African system, which he scrutinises not in a nakedly personal way but, rather in the manner of his master Brecht, through the equipment of a revolutionary critique." . Andries Walter Oliphant described "The Rivers Which Connect us to the Past": "These broad themes are given an African inflection and expressed with consummate craft in a variety of poetic modalities." , Jane Rosenthal described Horn's stories, as "ranging from the drily satirical to recreations of horror and dementia", they "leave an impression of savage intensity. Waiting for Mandela, one of the lighter stories, is about a pickpocket who attends the release rally with loot in mind. Here Horn achieves a bizarre and telling counterpoint of the apolitical indifference of this singleminded "skelm" with the lyrical majesty of Mandela.'s speech" .