AgResearch has been given approval to continue its work with genetically modified cattle to produce therapeutic proteins in milk.
The transgenic programme at Ruakura, near Hamilton was given a 10-year consent which is due to run out this year.
The Environmental Risk Management Authority has granted the new approval for double that time, 20 years, but with a review at 10.
AgResearch says the approval also allows the research to be extended to include sheep and goats.
The institute says the research could help alleviate diseases like breast cancer, diabetes and thrombosis.
ERMA says strict controls previously imposed on the research will continue. Some additional measures will also apply.
GE Free New Zealand, which has opposed previous AgResearch applications, is considering a legal challenge.
The organisation says AgResearch been given what amounts to carte blanche approval for genetically modified animal research which it regards as illegal.
The Green Party says ERMA has approved too much research, in one hit.
The approval will include the addition of human DNA to animal cells, but as before, Maori DNA will be off limits, out of respect for whakapapa, or Maori ancestry.