He questioned the whereabouts of their much-taunted solid economic management team.
According to him, the NPP lacks the credibility to be trusted to turn around the economy.
During the 2012 and 2016 electoral campaigns, the then-presidential candidate Nana Addo said that his team had the human resource to develop Ghana.
But Dr. Duffuor addressing delegates of the NDC from the Suhum and Ayensuano constituency said "They said they have the men, where are the men? The economy is in bad shape. Our debt is hovering around GH¢600 billion. When we [NDC] come we will prove to the NPP that we have the skills. We have done it before in 2009 when we took over the economy.
"We achieved single-digit inflation for 31 months. We will do it again. NDC we have the people but we don't talk too much. We will turn the economy around within two years when we come to power."
Ghana has reached an agreement with the International Monetary Fund (IMF) on a $3 billion bailout loan.
The country is facing more than 40 percent inflation, growing debt, and a sharp decline in its cedi currency since the start of 2022.
Finance Minister Ken Ofori-Atta said Ghana was committed to the programme and will work towards meeting the demands.
He said the agreement will help restore economic stability, tackle price spikes and strengthen the currency.