Te Whanau O Waipareira says it would not have poured money and resources into delivering a Government welfare scheme, if it had known the plug was about to be pulled.
The west Auckland urban Maori authority has taken the Ministry of Social Development to court over the loss of its Family Start contract - an intensive home-visiting welfare programme for at-risk families with babies.
The ministry says it took away the contract because of poor performance, but has not yet detailed what went wrong.
On Monday, the High Court at Auckland heard an agreement was reached so the trust could improve its Family Start service by bringing in new senior leadership and staff.
Chief executive John Tamihere said the trust was given an assurance that they would have time to boost their performance - but the Crown abruptly cut the contract.
He says the day that agreement was signed, his organisation was light years ahead and was in the top 10 of welfare service providers.
Mr Tamihere said the Crown was determined to terminate the contract when it should have acted in good faith, and supported the Maori authority.
The trust has a preferential right to deliver services to improve the lives of urban Maori in West Auckland, because it's clear the Crown hasn't, he said.
The case continues on Tuesday and the Crown will present its case later in the week.