Falling trade in certain goods and public holidays behind fall, according to Vietnam Customs.
Revenue from tariffs in the first four months of the year totaled VND77.4 trillion ($3.47 billion), or 28.67 per cent of estimates, according to the General Department of Vietnam Customs.
Export tax stood at VND1.59 trillion ($71.34 million), import tax VND19.45 trillion ($872.72 million), special consumption tax VND5.73 trillion ($257.10 million), value added tax VND50.35 trillion ($2.25 billion), and environmental protection tax VND160 billion ($7.17 million).
Revenue from tariffs in April reached VND21 trillion ($942.27 million), a decline of VND1.78 trillion ($79.86 million), or 8.4 per cent, against March.
Vietnam Customs put the April decline down to completely-built-unit (CBU) motor vehicles falling 6.4 per cent in volume and 12.4 per cent in value and iron and steel trade falling 17.4 per cent in volume and 12.2 per cent in value.
The two public holidays in April also had a negative effect on import and export activities.