The Deputy Prime Minister's keeping tight-lipped around details in key Government documents, set to be unveiled tomorrow.

Treasury's Half Year Economic and Fiscal Update and Budget Policy Statement are set to be released.

It's expected to reveal key fiscal metrics, including details of when a potential surplus may come to fruition - and where cost savings have been made.

David Seymour says the Government's holding the line on fiscal discipline - but won't give away any figures.

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