After doing as much research as possible in New Zealand, you need to visit Vietnam to confirm the results of your research, develop a deeper understanding of potential markets, establish relationships and eventually negotiate contracts and agreements.
You will almost certainly need to make a number of visits to do this.
New Zealand Trade and Enterprise (NZTE) recommends getting to know government and Peoples Committee officials and business people. Vietnam is similar to New Zealand in that it has different political and commercial centres.
Visits to both the commercial centre of Ho Chi Minh City and the government centre in Hanoi are also recommended.
Tap into the New Zealanders in Vietnam. There are about 300 working in Vietnam and they have built up a pool of knowledge that they will happily pass on to you over a coffee or a beer.
Some useful websites
Vietnam Chamber of Commerce and Industry
Ministry of Planning and Investment
Business Monitor Online
Vietnam News
Doing Business in Vietnam (blog)
Vietnam Business Protocol
Vietnam Briefing
Get general advice on how to identify and research your target market in the Export guide.