It follows a Freedom of Information (FOI) request by John Campion who is the Conservative candidate for the post in West Mercia.
It revealed since 2012 West Mercia has spent a total of£2.1m on temporary and agency staff with rises year-on-year.
Out of the three years the highest spend on recruiting non-permanent staff was in 2014/2015 with over £1m paid out.
During 2013/2014 the cost was £582,424 whilst over 2012/2013 police say they spent £481,151 on agency staff.
The force could not reveal the number of people hired for the cost or for which specific departments.
John Campion said: "It is mind boggling that millions of taxpayers' cash have been spent on temporary staff working in back room roles with the fact it has been rising year-on-year showing the commissioner has not a grip on finances.
“This shocking news comes as the current failed police and crime commissioner team want a 2% council tax rise to squeeze hardworking families.
“A rise is not needed in the first place when the Government has protected the policing budget whilst pumping more money into emerging threats like cyber-crime and extremism.
“If given the honour of becoming the next West Mercia Police and Crime Commissioner I will always use money wisely to cut crime and keep our community safe.”