"This result comes on the heels of our annual report which reflects our falling debt and strong budgetary performance after funding operational costs and capital works.
"The new rating should also provide stakeholders and the community with confidence that council promotes a strong management culture, fiscal discipline and high levels of financial disclosure to support council's prudent approach to financial management.''
In a report released in late September, the agency noted it expected the council's financial position to continue to improve as it benefited from strong revenue growth.
Sound financial management was helping the Western Bay of Plenty District Council achieve after-capital account surpluses and reduce its debt levels.
These stronger financial forecasts also support the council's liquidity position via higher cash reserves.
Since 2012, The Western Bay of Plenty District Council has shrunk its net debt from $144m to $80m and has budgeted $43m for capital works in this current financial year.