No explicit provision of law.
From the Intellectual Property Organization of Pakistan (http://www.ipo.gov.pk/patent/Default.aspx) :
Unpatentable Inventions In Pakistan
Discoveries of Laws of nature.
A productions.
Method or producing sound.
Computer Programs (Software).
Perpetual motion machines.
a method of writing music.
A fancy name for an article.
A trade mark.
The discovery of new properties of known substance.
A system of alphabet.
Chemical & Pharmaceutical product (till 2004).
A system of shorthand.
Literary, dramatic, musical and artistic works.
Doctor's prescriptions and Patent Medicines.
A system of indexing.
Mere charts, diagrams, or printed sheets.
A surgical operation.
Articles harmful to public heath & their prosperity.
Treatment of human beings, animals, flowers & plants.
Purely scientific & mathematical formulas & principles.