But Guy Vassall-Adams, a barrister at Doughty Street Chambers in London, said few organisations were making the most of the tools available.
"A number of environmental NGOs have been extremely effective at using the Freedom of Information Act, but it's still a relative novelty to many," he said before the event.
"There are misconceptions about it being complicated, time-consuming and potentially costly. Even if a request is refused, it is possible to seek an appeal at the Information Tribunal without legal representation."
The event will offer practical guidance from several lawyers from Doughty Street Chambers and will also cover defamation.
"In the past few years, the courts have developed a public interest defence that offers much better protection," said Vassall-Adams. "It isn't risk-free, but as long as you are careful it's a good time to campaign."