Released earlier this week, the bank's global and Australian economic forecasts said concerns about Greece exiting the eurozone have raised both financial market volatility and downside risks to global growth.
However, the problems in Greece have had "much less impact than earlier episodes" – mainly due to the improved support systems for sovereign debt that are now in place, NAB said.
"[European Central Bank] bond buying and [European Financial Stability Facility] lending ... have resulted in much lower upward pressure on eurozone periphery bond yields.
"The pattern of exposure to Greek debt has also changed with eurozone agencies now holding most of Greece’s government debt and banks winding back their once sizeable exposure to the country," the report said.
Furthermore, it is the "apparent bursting of the Chinese equity market" that should be causing global investors the most concern, NAB said.
According to the report, the equivalent of US$3.5 trillion has been wiped off the Shanghai and Shenzhen stock markets since their peak in mid-June 2015.
"Such a loss of wealth, even with short-lived paper gains, should have an impact on the economy, partly through margin-lending deals going sour as the sharemarket fell," NAB said.
When it comes to the impact of Chinese and Greek problems on Australia, NAB has not changed its forecasts for Australian growth – with GDP set to grow 2.4 per cent in 2014-15, 2.6 per cent in 2015-16 and three per cent in 2016-17.
"It is difficult to access the impact of recent international events such as Greece and more importantly China – on confidence and further falls in commodity price," the bank said.