...data due to methodology changes, the office said on Tuesday.
"All the methodology changes result in lower overall import and export figures for 2006 and individual months of 2007," the office said in a statement.
"A decline is stronger for overall imports, which would mean improvement in the trade balance," it said.
The revised data will be released in October at the latest.
Changes will affect how electricity, trade and indirect exports and imports to and from non-European Union countries are reflected in the statistics, the office said.
Estimates of imports using the free on board (FOB) shipping method will also be more accurate, the office said.
Data showed earlier on Tuesday that Slovakia's trade deficit shrunk to 1.782 billion crowns ($72.91 million) in July, from this year's record gap of 5.551 billion in June.