Labor frontbencher Tanya Plibersek will warn her party against the "insulting simplicity" of public debate on national challenges such as climate change and inequality, in a speech on Sunday dealing with trust in politics.

Ms Plibersek will acknowledge the failures on all sides of politics in regaining the trust of voters, telling a Labor conference the problem includes corruption scandals in their own party's NSW branch.

Labor frontbencher Tanya Plibersek. Credit:Alex Ellinghausen

"It will take common sense and common decency to regain people's confidence," she says in a draft of a speech to be delivered on Sunday.

"That means being prepared to tackle the hard issues without resorting to insulting simplicity: the ongoing problem of stagnant wages and an insecure labour market; climate change and energy policy; the persistence of inequality and its disproportionate impact on young people.