"It is a rating system Treasury do for themselves," he said.
Mr Brownlee has blasted previous Treasury reports as "disrespectful", calling a November report on anchor projects "utter tripe".
The latest Treasury report said the improved mark was because "early design and master planning stages" had been completed.
But the Avon River Precinct project had no improvement from the amber rating.
The Metro Sports Facility rates amber/green, the same as it was in the last Treasury report.
The East Frame Residential project has been evaluated for the first time by Treasury and has also received an amber/green.
The convention centre's amber rating means that successful delivery "appears feasible" but significant issues exist that could be resolved.
It comes after Plenary Conventions New Zealand, made up of Carter Group and Ngai Tahu Property, pulled out of the project in June.
The convention centre has been shrouded in controversy, with the Government deciding it would do the $284 million project alone, after the relationship with Plenary broke down.
The Star revealed recently that the project, which is set to open by the end of 2019, had already cost $74 million.
An assessment of schedule risk is expected to go to Cabinet in November.
Labour spokeswoman for Canterbury Issues Dr Megan Woods said it was a "pat on the head" for the Government but there was "still room for improvement".
She said it showed since the April exit of the Canterbury Earthquake Recovery Authority there had been improvements.
"It shows that a locally-led recovery is better than a centrally-led recovery," she said.
Mr Brownlee said Dr Woods' comment showed how out of touch she was.
Otakaro Ltd took over the anchor project from CERA.
"Otakaro is a Government-owned entity," he said.
Ōtākaro Ltd chief executive Albert Brantley said the report showed Ōtākaro had "hit the ground running".
He said work on the Metro Sports Facility and the East Frame sites would be underway before the end of the year, and work on the Avon River Precinct was progressing well.
The budget for the Avon River precinct, which includes the Margaret Mahy Family Playground, The Terraces, Victoria Square redevelopment and the North Frame community spaces and garden, is $116 million. The remaining projects are set to be complete in stages next year.
The $800 million East Frame Residential project is set to include almost 1000 townhouses and apartments, to be built in stages completed between 2018 and 2026.
The $300 million Metro Sports Facility was originally scheduled to be finished this year, but is now set to be complete by 2020.
The Christchurch Schools Rebuild Programme, to repair and rebuild 115 earthquake damaged schools by 2022, improved with a top rating of "green".
