Prime Minister John Key isn't dropping many hints about what he's set to announce in his speech at the National Party's annual conference, but he's confirmed he will be talking about asset sales.

The conference, which got under way on Saturday, is the party's first big gathering since last year's election with more than 500 delegates packing Auckland's Sky City convention centre.

Mr Key told reporters his leader's address on Sunday will have an economic focus.

He said he will "firm up" some of the details around the government's plan to partially privatise four state-owned energy companies, but he was not prepared to comment further.

On Saturday, Finance Minister Bill English said the economic challenges facing the world are not going to go away for a generation.

He told conference delegates that the economic challenges facing New Zealand remained large.

To coincide with Mr Key's speech, Auckland Action Against Poverty will protest against the government's economic and welfare policies.

About 100 protesters were met by dozens of police when they marched from Britomart to the conference venue on Saturday to protest the government's education policy.