Data published by the National Police Chiefs’ Council (NPCC) shows Northumbria Police issued 278 fixed penalty notices between March 27 and September 21 – with Durham Constabulary handing out 178.
Neither force has issued notices within the last month.
In total, 18,912 lockdown fines have been issued in England and Wales so far, though just 151 of these occurred in the five weeks to September 21.
NPCC chairman Martin Hewitt said: “It is crucial that people do everything they can, including limiting social contact, to reduce the spread of coronavirus. The country is at a critical point, and personal choices will matter in the weeks and months to come.
“Thank you to the vast majority of the public for sticking to the rules and following the guidance in place to limit the spread of the virus.
"A small minority, however, are not following the rules, and are making decisions which put lives at risk – they should expect to have enforcement action taken against them.”
Police forces can issue a £60 penalty, reduced to £30 if paid within two weeks, for breaches of the lockdown rules.
Separate data published by the NPCC shows no fines have yet been recorded by police in Northumbria or Durham for people failing to self-isolate after returning from a country on the Government's quarantine list.
Neither have also given out fines to people for failing to wear a face covering on public transport or in shops, with 89 elsewhere in England and Wales.