"There is no doubt Saddam was guilty of serious human rights crimes and crimes against humanity, but that does not make the death penalty acceptable," Tuomioja said on Saturday.
"The European Union has been consistently against the use of the death penalty," he added. "It could also prove to be divisive for the future of Iraq, especially since there has been serious criticism of the way the trial was conducted."
The Finnish foreign minister said the execution was no surprise since proceedings against Saddam had been going on for some time.
Three other Nordic countries, Sweden, Denmark and non-EU member Norway, also criticized the execution, citing their opposition to the death penalty.
The former Iraqi dictator was hanged at dawn at an intelligence facility in Baghdad. He was convicted last month of crimes against humanity. YLE, DPA, AP