China, India and the Republic of Korea were three biggest buyers, it said.
Exports to these markets all increased sharply in the first four months with exports to India enjoying the highest rise of 29 percent.
Overall exports in the first four months went up 13.7 percent to 556.9 million USD.
But they plunged in May to just 105 million USD.
China is by far the biggest importer of Vietnam’s natural rubber, accounting for some 60 percent of volume, most of it used to produce tyres, analysts said.
Therefore, the US’s imposition of high taxes on automotive components imported from China has impacted Vietnam’s rubber exports to China, they said.
The Ministry of Agriculture and Rural Development has urged rubber producers and exporters to diversify their products and look for other export markets to reduce the reliance on China.
They should focus on the Indian market, whose tyre industry has developed rapidly but lacks local rubber supply, it said.
The Vietnam Rubber Group (VRG) will work to have Forest Stewardship Council (FSC) certifications for all of its rubber forests as part of the sustainable development programme for 2019-2024 tenure.
The VRG plans to zone off 5,000 ha of forest land in its rubber project area for regeneration, and encourage its members to apply clean production and sustainable management measures to further develop the VRG brand.
In the last seven months of 2019, the group will update its regulations on social and environmental responsibility and recruitment policies, and approach the FSC standards.
According to VRG Chairman Tran Ngoc Thuan, the sustainable development programme is a must in the context of global integration as most of the importers require products to have clear origins and FSC certification, which ensures products come from responsibly managed forests that provide environmental, social, and economic benefits.
The country has one million hectares under rubber.
Vietnam is the third biggest natural rubber exporter, shipping over 1.5 million tonnes annually to more than 70 countries and territories.
In 2018, exports fetched 2.1 billion USD, a 6.6 percent decline from 2017.