Hundreds of botanic garden enthusiasts from 45 countries have arrived in Dunedin for the Fifth Global Botanic Gardens Congress.
The Congress, which starts today, has attracted 329 delegates. The week-long programme of events coincides with the Dunedin Botanic Garden's 150th anniversary.
In tandem with the congress, the Sixth Biennial Botanic Gardens Australia and New Zealand Congress is also being held.
It was anticipated the events would bring about $2 million to the city.
Delegates were coming in the largest numbers from Australia (61), New Zealand (60), the United States (58), China (29) and the United Kingdom (27) as well as from Europe, Ethiopia, India, Nigeria, Russia and Mexico.
Dunedin Botanic Garden team leader Alan Matchett said it was an exciting time for the garden and city.
''We are looking forward to welcoming delegates and their guests and showing them the city's wonderful attractions and facilities.''
Botanic Gardens Conservation International Board of Directors chairwoman Baroness Joan Walmsley was also attending the conference.
A video address from Dr Braulio Dias, the United Nations Convention on Biological Diversity executive secretary, would follow the opening.
Delegates would be attending a range of symposiums, workshops and field trips during the congress, based at the Dunedin Centre.
An address by Dr Richard Benfield from Central Connecticut State University on garden tourism will be open to the public. Organised by the Friends of the Botanic Garden, it will be held in the Botanic Garden Information Centre on Wednesday night.
Also on Wednesday night, Melbourne Royal Botanic Garden chief executive Tim Entwisle will host an open panel discussion at the Glenroy Auditorium, which will include Royal Botanic Garden Edinburgh Queen's botanist Prof Stephen Blackmore, Auckland Botanic Gardens curator manager Jack Hobbs and Chicago Botanic Garden chief executive Sophia Shaw Siskel.