Action on Empty Homes say it is "exceptionally worrying" that more than half a million homes lie unused in England, while tens of thousands of families are living in temporary accommodation.
The campaign group's analysis of Ministry of Housing, Communities and Local Government figures show that 3,160 homes in the city were not being used as of October – up from 2,949 the year before.
Of these, 2,293 were long-term vacancies – unoccupied for at least six months – and 867 were second homes.
That means one in every 41 homes in Sunderland were out of use – above the England average of one in 47.
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There were 268,000 long-term empty homes across the country – 19% more than the previous October.
Action on Empty Homes said that the 531,000 properties in England without residents could instead offer "vitally needed housing" to the homeless.
Director Will McMahon said: “It can’t be right that in the last four years we have seen an escalating housing crisis while the number of long-term empty homes keeps rising.
"It will be impossible to ‘build back better’ if we keep letting our housing crisis get worse."
An MHCLG spokesman said: “We have given councils powers and strong incentives to tackle empty homes, including the power to increase council tax by up to 300% on these properties, and take over the management of homes that have been empty for a long period.”