There were also outstanding contracts for "armoured vehicles, ballistic vests, night vision binoculars and three unmanned aerial vehicles".
Other armoured vehicles delivered in 2007 for peace-keeping operations in Sudan "scandalously broke down."
"Many of the contracts were characterised by lack of due process, in breach of extant procurement regulations and tainted by corrupt practices," said the statement, describing the findings of the interim report which audited procurement contracts from 2007 until 2015.
The presidential report is designed to guide Nigeria's anti-graft agency, the Economic and Financial Crimes Commission (EFCC), in their criminal investigations into corruption in Nigeria.
During the raging Boko Haram insurgency, Nigerian troops reported that they were under-equipped to fight the insurgents, who had captured a chunk of the country's northeast in their quest to create a hardline Islamic state.
Buhari said in December last year that the Islamists were "technically" defeated, though sporadic attacks still happen in Nigeria.
The EFCC is investigating and has charged some military bigwigs -- almost exclusively belonging to the opposition party -- with corruption, causing critics to say Buhari is using the corruption war as a way to silence dissent.
But Buhari has maintained his anti-graft war shows no bias.
"Whoever deter us from fighting corruption will suffer the consequences," Buhari warned earlier in July.