UPDATED 10.52AM: The High Court has decided that lobby group Family First can appeal a decision that had it de-registered as a charity.

The Charities Board decided to de-register the controversial lobby group in 2013 - according to Family First, this was because of its opposition to gay marriage.

Justice David Collins has told the Charities Board to reconsider its decision.

It follows a precedent set by a Greenpeace judgement last year, where the High Court ruled that charities can engage in political activities.

Family First National Director Bob McCoskrie said some charities have to advocate for political issues to support their concept and he hopes the Board will recognise this in future.

"Previously the Charities Board has been pretty inconsistent about that issue. The Supreme Court and now the judge's comments in our case mean the Charities Board has got to be a lot more realistic," he said.

"There's a misunderstanding between a group that works with an ambulance at the bottom of the cliff and somebody who puts an ambulance at the top of the cliff."

"There are many charities who do one or the other or both."