"On Monday, we will present measures to combat the shadow (economy) that will be unprecedented and will make it disadvantageous to stay in the shadow," he said on the Žinių Radijas radio station.
Šapoka would disclose no further details about the proposed measures.
The minister said in February that curtailing the shadow economy might open the way for lowering taxes.
Based on different estimates, Lithuania's shadow economy accounts for between 15 and 30 percent of GDP.
The government is currently finalizing its work on structural reform measures that will cover an overhaul of the tax and pension system, certain innovation, education and healthcare changes, and new steps to cut down on the shadow economy.