Does the dole centre have the power to force you into volunteering, ie sanction me and cut my benefits? My work coach has been pushy about trying to get me to do volunteer work to make up for a lack of "recent job experience", which I've already explained away in my CV as being a freelance consultant.
Most likely yes. Assuming you're subject to the work search requirement, then ADM J3063 would apply, which reads as follows:
A claimant who has not taken all reasonable action to obtain paid work has to be treated as not having complied with a work search requirement. Reasonable takes it's ordinary meaning of fair, sensible and as much as is appropriate in the circumstances.
If your work coach recommends doing something because they think it would improve your chances of getting paid work, then you're expected to do it under threat of sanction unless a) you can prove to a decision maker that it wouldn't actually improve your chances of getting paid work or b) you can prove to a decision maker that it's unreasonable. Your only plausible get-out would be if (for example) doing the voluntary work would mean that you'd have to give up a training course or you wouldn't be able to attend a job interview that you've already been offered.