Australia and New Zealand Banking Group Ltd said that the political deadlock and "inappropriate government policies" will pose risks to the city's long-term economic competitiveness. "In our view, inappropriate government policies (reducing the scale of the Individual Visit Scheme and tight stamp duty policy) pose bigger risks to the economy as Hong Kong will lose its unique advantage that allows it to benefit from growing cross-border flows," ANZ Bank said in a note.

Ryan Lam, a senior economist at Hang Seng Bank Ltd, said that the bank had revised its estimate for Hong Kong's 2014 full-year economic growth from 3.3 percent to 2.8 percent.

Tiffany Qiu, an economist at Royal Bank of Scotland Group Plc, said that Hong Kong's economic growth will to be modest, as the global trade outlook has been tepid the past two months. Qiu noted subdued mainland tourist spending and pointed out that the city's commercial property sector is facing major headwinds. The investment bank cut Hong Kong's economic growth forecast for 2014 from 3.2 percent to 2.4 percent.

Despite the warnings, S&P affirmed the city's "AAA" long-term and "A-1+" short-term ratings, with a stable outlook, reflecting the city's above-average growth prospects for a high-income economy, consistently healthy fiscal performance, sizable fiscal reserves and strong external position over the next 24 months.

S&P estimated Hong Kong's 2014 per capita GDP at $40,500.

As of June 30, the SAR's fiscal reserves stood at HK$735.8 billion ($95 billion).