The conference will debate whether the Communications Act should be amended to allow 'political' advertising by charities.
Steve Tibbet, head of policy at ActionAid, and Rosamund McCarthy of Bates, Wells & Braithwaite, will lead calls for the Act to be changed to allow charities' campaigning messages to be heard.
Last year, Make Poverty History's 'click' advert was banned from TV because it was deemed political by the regulator Ofcom. Some think the ruling could have implications beyond MPH and affect campaigns such as Stop Climate Chaos.
McCarthy told Third Sector: "The MPH decision could have a trickle-down effect that will inhibit charities from being radical and result in greater caution.
"Charities must be careful that the right to campaign is protected and enhanced. There should be a guarantee that, if you sign up to certain principles, then your right to campaign is assured."
McCarthy will also address new criminal law restrictions on campaigning and the increasing trend for businesses to take out civil injunctions to stop campaigners.
Tibbet said: "If government and regulators want to encourage campaigning, they should make the rules clearer and send a signal that it will be allowed."
- See Editorial, page 22.