Only 'e-customs' infrastructure for air cargo clearance remains to be installed and the hardware is expected within a week, Goonewardena said.
Once the system is running importers could submit customs documents up to 24 hours before a vessel arrives in Colombo.
"If all the taxes are paid, you can clear the cargo in 'zero time'," Goonewardene told members of the Import Section of Sri Lanka's Ceylon Chamber of Commerce.
Importers play a crucial role in the economic freedoms of the poorest sections of society especially in smaller countries, where there are is insufficient domestic competition allowing.
Critics say in Sri Lanka predatory nationalist businesses have been increasingly able to rig the customs system in their favour to block imports and earn extra-normal profits (rents) in recent years.
Protected nationalist businesses earn rents by collecting the difference between import taxes and the production cost, a channeling of taxes that would otherwise have gone to the state in their own pockets that is known as tax-arbitrage.
Sri Lanka's importers provide nearly 60 percent of the taxes spent by the state and rulers, even though they are vilified by nationalists and rent seekers.
Fast cargo clearance is also vital for the export industry which imports many inputs to process.Fast import and export documentation cuts costs making good cheaper for end users in both Sri Lanka and abroad.
Goonewardene said eventually Customs hoped to eventually clear between 50 to 60 percent of the cargo without inspection.
Inspections are carried out typically to prevent customs fraud through undervaluation to prevent prohibited goods from entering the country, or when officials have some reason to suspect that declarations are not correct.
There will also be periodic routine 'post-audits', Goonewardene said.
The electronic documentation system will also be connected to other agencies such as revenues, standards and quarantine to get relevance clearances and also allow cross-checking to prevent fraud.
Goonewardene said initially a hard copies would have to be submitted until the automated system's reliability is established so that documents could still be cleared manually if the system went down temporarily.