Lovrak wrote realistic short stories and novels for children.

His most famous works are "Vlak u snijegu" ("A Train in the Snow"), "Družba Pere Kvržice" ("Pero Kvržica's Gang").

"Vlak u snijegu" has been translated into German, Hungarian, Polish, Czech and Slovene language.

His works emphasized love for children, the beauty of nature and the pursuit of social justice.

Lovrak made a great impact on Croatian literature for children and influenced other writers.