Jaswant Singh's remarks came at a time when his Bharatiya Janata Party (BJP) is targeting the government on the VVIP chopper deal and comparing the scandal to Bofors scam of the late 1980s.
"I am pained and sad that the accused in this is an Italian company. It seems that we have forgotten them. What we are focusing on is only what did the (IAF) chief do. The Air Chief Marshal is a distinguished retired officer. We should not casually denigrate these higher officers of the armed forces," he said.
Singh, however, accused the defence ministry of sitting over the matter, after the Italian investigators had indicated corruption in the deal.
"...a damage to decision-making by such programmes being hidden with corruption. I find the government's response tardy and unsatisfactory... certainly not answering the need of the hour," he said.
"We need an expeditious and fair probe. Don't rush to conclusions and denigrate the former air force chief. A thorough probe must be conducted into the entire matter so that all hidden facts are cleared and the truth comes out," he added.
Meanwhile, former IAF chief Tyagi denied any wrongdoing after a preliminary inquiry report filed by prosecutors in Italy Tuesday sought to link him to the corruption charges.
The Indian defence ministry Tuesday ordered a Central Bureau of Investigation (CBI) probe into the deal for 12 VVIP AgustaWestland helicopters for IAF.