The data, based on a survey of 24 mainly non-US banks, found most are confident they meet current regulatory requirements.
However, the report said many are underestimating how many people will be needed to deal with tougher regimes and pointed out 90% of respondents had fewer than 20 people dedicated to working on stress tests.
This was said to be around half of the number employed by banks in the US for the same functions. The majority of respondents also had no plans to recruit any additional people in the next three years although they acknowledged a need for increasing investment.
Keith Ackerman, PwC financial services risk and prudential partner, said: "The way global banks prepare for stress testing needs to change. Past experience has shown that very demanding regulatory stress testing regimes require larger teams with the appropriate skills."