The crowd at the city's war memorial included former PoW Len Gibson, who was captured at Singapore and forced to work on the Burma Death Railway.
A commemoration was also held at the Burma Star Memorial at St Thomas' Church in Newcastle.
The Queen and the Duke of Edinburgh led a remembrance service in London.
Mr Gibson, 95, said it was "nice to see these people still remember".
"It was such a horrendous time that it's in my memory - every day there's something occurs that reminds me of those times," he said.
"They [their Japanese captors] treated us as slaves.
"If we didn't work hard they'd beat us with sticks.
"We'd wouldn't have minded working hard if they'd fed us, but they starved us."
The memorial's organiser, Sunderland Armed Forces Network chairman Graham Hall, said it was important people continued to remember.
"If nothing else it's a reminder of the inhumanity we keep on perpetrating our fellow mankind," he said.
Sunderland had the highest proportion of veterans of any city in the country at over 26,500, he added.
"I doubt whether there's many families that haven't been affected by service life in one shape or another."
Prayers have been said and wreaths laid at a service in Sunderland to mark the 70th anniversary of VJ Day, the end of the war with Japan and World War Two.