Museums Sheffield has blamed the credit crunch and a redevelopment project for nearly £600,000 of debt.

Over half of the debt has been carried over from the Weston Park Museum scheme, which ended 2006, said a spokesman.

The remaining debt, accumulated during 2007-08, because of rises in energy costs. Nick Dodd, the chief executive of Museums Sheffield, said: "These costs have put unique pressure on our budgets [and came] when our income started to dip with the effects of the economic slowdown."

The museum trust has made cuts to its 2008-09 marketing budget and is discussing the issue with its main funder, Sheffield City Council. A spokesman said: "This is not a sustainable position. It is a concern."