HR should apply the same standards to recruiting interims as it does to hiring permanent staff, according to IM experts.
The interim sector reports that too many clients are failing to give interim supply companies a detailed brief or are tasking up to six different agencies to fill one post.
Nigel Corby, managing director of IM consultancy Global Executives, said: "Some clients instruct a number of agencies, which is a waste of everyone's time. We are not a body shop, but a bespoke partner.
"IM companies should be treated as partners. We need a proper brief, including the company culture, background to the job, the deliverables and the key tasks."
Although the hiring of an interim is led by the HR department, it is important that the managers who will be dealing directly with the interim and signing off the assignment are involved in the selection process.
Richard Jones of PricewaterhouseCoopers said: "There is no way a line manager would take someone on without interviewing them first - the same goes for an interim.
"It is the people working with the interim who will make the decisions about the task ahead, so they must be involved from the beginning."
Interim agencies have complained about potential clients who do not have the budget to hire an interim, but indulge in 'tyre kicking' to see who may be available should they opt for the interim route.
Some companies even use the interim selection and interview process to gather 'free consultancy advice' from interims who are experts in their field.
Ian Daniel, chairman of the Interim Managers Association, has been working to raise standards in agencies and devise a code of practice for interim managers. He said: "Perhaps the third leg is to raise the standards of how client companies use us and treat us."