The Constitutional Court, in a ruling issued late Wednesday, said the panel of nine judges "admonished" prosecutors for pursuing cases where remarks allegedly insulting Mugabe were made "in drinking halls and other social places."
Such prosecutions only brought more disrespect toward Mugabe, it said
At least 80 such cases have been heard in recent years, leading to brief imprisonments or fines.
The ruling ordered the justice minister to appear in court Nov. 20 to justify continued enforcement under a new constitution that protects free expression.
A Zimbabwean artist whose exhibition on political violence depicted Mugabe daubed in red paint has also appealed against the insult laws.