Adel Jubeir, foreign affairs adviser to de facto ruler Crown Prince Abd Allah, said on Sunday that Saudi Arabia stood by its insistence that the men - five Britons, a Canadian and a Belgian - carried out the bombings which killed one person and wounded several others.
"What happened is there was a series of explosions that were perpetrated by rival gangs who were involved in smuggling alcohol. We have the evidence, we have the proof and we stand by it," Jubeir told BBC radio.
"(King Fahd) has the right to pardon people and he exercised that right. He felt it was in the best interest of the nation and in the best interest of our relations with Great Britain."
Families of the men said their confessions, which were later retracted, were obtained under torture.
Saudi authorities blamed the violence on a turf war over illegal but lucrative alcohol sales.
Jubeir denied that. "Let them be examined by medical doctors and we will see," he said.
The men were accused of carrying out several bombings in Saudi Arabia in 2000 and early 2001. Saudi authorities blamed the violence on a turf war over illegal but lucrative alcohol sales. But their lawyer said any money involved in such sales in the conservative Muslim kingdom would not justify resorting to murder.
Continued violence against Westerners in Saudi Arabia after the men's detention in early 2001 also pointed to domestic groups being behind the attacks, analysts say.
Thirty-five people were killed two months ago in triple suicide attacks, blamed by Saudi authorities on al-Qaida bombers, at three Western residential compounds in Riyadh.
Since then Saudi Arabia has cracked down on various groups, leading to a series of arrests and bloody clashes in which 16 suspects and 11 Saudi police have been killed.