In the Rummerys' case, the couple signed an initial 15-year tenure at $100 a hectare a year for 210 hectares in the dry Namoi River region near Walgett.

"This will return a meaningful amount of income to the overall farm business and certainly help in periods of no agricultural production from the other areas on the farm due to drought, et cetera," Mr Rummery, an agronomist said.

The protected zone, part of a 1000-hectare property, contains the riverine corridor and the area's most diverse range of species such as striped wallabies, coolibah and blackbox eucalyptus.

"It is obvious that there are key parts of the landscape where the land-use should not be based on an agricultural outcome," Mr Rummery said. "Rather...there is a more intrinsic value, such as that of delivering environmental and conservation [results]. However, until the [trust] program we have not had an equitable or workable framework for this to occur."

Matt Kean, the Energy and Environment Minister, said the trust had conserved some 29,000 hectares in 133 agreements since the $350 million, five-year program was set up a year ago.

“The response from landholders to these conservation tenders is overwhelmingly positive,”
Mr Kean said.

“We have some of the most beautiful landscapes and pristine natural areas in the country," he said.

The Audit Office's recent native vegetation report found the trust's operations and those of its predecessor, were "not always consistent" with conservation priorities.

"For example, one region of the state has received the largest proportion of funding, but the areas selected for conservation have the lowest biodiversity values," it said.

In addition, "although some measures are in place to preserve investments in perpetuity, [the trust is] yet to finalise procedures for monitoring compliance with conservation agreements," the auditor report said. The Trust itself is not set up as regulator to enforce the agreement.

Mr Rummery said his obligation includes managing both weeds and feral animal pressures.