The UK faces an increase in major incidents such as severe weather, financial crises and data security lapses, according to a report.
Insurance firm Zurich also forecast a rise in industrial action over the next five years.
A survey of more than 120 chief executives or directors of public sector organisations including those in health, education and local government, showed over half said their ability to deal with a major incident could be hit by lack of finances.
Around half of those polled believed their financial reserves will be drained over the next three years.
Anne Torry, managing director at Zurich Municipal, said: "Against a climate of tough decision-making and cuts for public sector organisations, our research shows that many are being forced to dip into their reserves just to continue delivering core frontline services.
"This means there will be little spare cash to draw on if disaster strikes."