There's a letter in today's Irish Times from the press office of the D/SP confirming that volunteering is not only allowed, but staff have been reminded to inform people about it.

"The Voluntary Work Option permits jobseekers who engage in voluntary work within the State to engage in such work without it affecting their entitlements. The aims of the Voluntary Work Option are: to encourage voluntary organisations to involve jobseekers to the greatest extent possible in their existing activities by creating new opportunities for voluntary work; and to inform jobseekers of their freedom to involve themselves in voluntary work and to encourage them to do so."

http://www.irishtimes.com/letters/