The game between Manchester United and Bournemouth at Old Trafford stadium in Manchester was called off yesterday after the fake bomb was discovered in a toilet close to kick-off time.
A controlled explosion was carried out on the device, which police said was accidentally left by a private security firm.
Greater Manchester's police and crime commissioner, Tony Lloyd, today said it was necessary to find out how the bogus explosive was left behind by a security company.
"This fiasco caused massive inconvenience to supporters who had come from far and wide to watch the match, wasted the time of huge numbers of police officers and the army's bomb squad and unnecessarily put people in danger, as evacuating tens of thousands of people from a football stadium is not without risk," he added.
More From This Section
The discovery of the dummy bomb prompted the evacuation of the 75,000-seat Old Trafford stadium minutes before Manchester United's last game of the season was due to start.
Detailed examination by Greater Manchester Police (GMP) found the suspect package, thought to consist of a mobile phone attached to a pipe, had been identified as a training device.
GMP in a statement last night said, "Shortly before today's planned football fixture, which was due to kick off at 3 pm, staff from the Manchester Unitedground alerted police to a suspicious item that had been found.
"Police quickly attended and explosives experts were called in to assess the item, which has been described as an incredibly realistic-looking explosive device.
The Premier League match has been rearranged for Tuesday at 20:00 local UK time.
However, Manchester United will refund all tickets and allow ticket holders from both clubs to watch the re-arranged game for free, while Manchester United season ticket holders will also be given a credit.
The gesture is estimated to cost Man United around 3 million pounds.