Traders are competing to buy from provinces such as Dak Lak, Binh Phuoc and Tien Giang.
Hoa An, a trader, said demand in mainland China has been rising and therefore traders are willing to pay high prices to meet its needs.
Other markets such as Japan, Hong Kong, Taiwan and Australia are also buying more Vietnamese durian, he added.
Another trader, Manh Khuong, said Thailand has run out of supply for now and therefore Chinese buyers are sourcing more from Vietnam.
But the Thai durian crop is set to ripen in another two weeks, and Vietnamese prices are likely to drop then, he added.
Dang Phuc Nguyen, general secretary of the Vietnam Fruits & Vegetables Association, said since May China has doubled its monthly purchases of Vietnamese durian.
Vietnam’s exports were worth nearly $500 million in May and are estimated to reach $600 million in June, he said.
This means the country exported around $1.5 billion worth of the fruit in the first half of the year, he said.
"More stringent quality control is needed to ensure the country meets its full-year export target of $3.5 billion."
Vegetable and fruit exports overall are expected to rise by 15-20% this year to around $7 billion.