"You must attend board meetings, you must be reading board papers, asking the right questions and ensure you use the knowledge you have been selected for," he told a bank directors’ symposium organised by the regulator.
"We need to see those skills being used at the banks themselves," he told the forum attended by around 200 chairmen, directors and chief executives of 33 licensed banks.
"We have to admit not all those skills are being used. We want to see them being made use of at the board room."
Cabraal said bank directors should closely monitor the work of their chief executive officers, get involved in preparing strategy and be more aware of their institutions' financial health.
"You should keep your CEOs on their toes, ask the tough and probing questions so they live up to the scrutiny and play your part in preparing strategy - we want to see input from you as well," he said.
"You've got to know where the bank will be in five years time, know from where you get funds, to which sectors you lend, the succession plan.
"Directors will have to take more interest to ensure answers to questions."
Directors of banks should also familiarise themselves with new developments in the banking sector and new rules that are coming into effect.
"You also need to protect high standards in your staff, ensure the fitness and propriety of your staff and achieve oversight through sub committees."
Bank directors were also responsible for ensuring the banks complied with new central bank directives on a 'customer charter' to ensure they treated customers in a fair manner.
Cabraal said it was important for directors to ensure the financial health of their individual institutions as they were all connected and problems at one could spread through the entire system.
"All banks are interconnected. If one bank fails, others fail. You must ensure safety first," Cabraal said."If you are safe all the others will also be safe and no one can inflict any contagion effect on the other."