Dunedin City Council sources, and those involved in the garden, last week criticised an archaeological report prepared by Southern Pacific Archaeology Research, and the direction of the trust.
The report suggested the garden, to be built within the Dunedin Botanic Garden, be built elsewhere, because there may have been a building there in the past.
Much of the funding for the project had come from a bequest from Nancye Sime, a noted chrysanthemum and rose judge who died in 2004, aged 87.
Trust Otago-Southland area manager, Owen Graham, said it had been unjustly criticised.
He said the report was commissioned by the council and had not been sighted by the trust.
"Consequently, we are not in a position to recommend any actions or make any demands on the council at this time."
The trust had advised a council-convened working party in 2000 there was a possibility work at the garden would uncover archaeological material from pre-European and early European activities.
This year, it had provided advice to council staff on procedures for the development, including seeking an independent archaeological assessment for the site.
Mr Graham said the trust had a responsibility to promote the identification, protection, preservation and conservation of the historical and cultural heritage of New Zealand, and a statutory responsibility to administer the archaeological authority process.
"The discovery of the very important wooden causeway at the council's Wall Street development site last week is an extremely good example of the reasons why the trust's archaeological authority process is in place."
He said the trust had not been responsible for any delays. Criticism of it fulfilling its statutory obligations were unjust and comments its activities "bordered on frivolous" were wrong.
The trust would quickly review the assessment once it was provided, and advise whether an archaeological authority was needed.
