The revised estimates report predicts a $56.6 million deficit for the 2015-16 financial year, almost $2 million less than expected, which Treasurer Peter Gutwein says would be the best budget result in five years.

Mr Gutwein said the 2015-16 result was courtesy of a ''sensible and responsible'' fiscal approach. 

The update flags a deterioration of $143.5 million across the forward estimates.

Labor Treasury spokesman Scott Bacon said the report did not fully take into account the budgetary impact of a long firefighting campaign, the outbreak of POMS disease on the oyster industry and challenges faced by Hydro Tasmania to safeguard the state's energy security. 

Forecasted Hydro dividends and income tax equivalents have been reduced by $54 million, but the report says the full financial impact of its struggles won't be known until closer to the 2016-17 budget.

The report doesn't list help to the oyster industry in the report, and says the full cost of flood and fire damage to the state is currently unknown, but believed to be significant.

Mr Gutwein said despite the surpluses predicted across the forward estimates, ongoing fiscal discipline would be required to deal with risks and ongoing challenges.