VGDISPLAY as nagios user


I’ve a script to check ho wmuch free space a certain VolumeGroup has. If i run the command as root, i get the corret output. When i run it under the nagios user account, i don’t get the free size displayed.
The reason for this is that the nagios user is not authorized to use the vgdisplay command.

Any suggestions how i can get thids to work without running into security issues?

os : CentOS 5.4