According to a joint investigation by the Guardian and Daily Mirror, Mr Cummings was spotted twice in the North East over the course of nearly a week, between March 31 and April 5 - eight days after lockdown began.
The trip took place at the end of March, just days after the Prime Minister announced strict lockdown measures, including banning all non-essential travel, and giving the police powers to impose fines on anyone breaking lockdown rules.
A spokesperson for Durham Constabulary said: "On Tuesday, March 31, our officers were made aware of reports that an individual had travelled from London to Durham and was present at an address in the city".
Downing Street has always refused to confirm where Mr Cummings spent lockdown.
Durham Police confirmed officers had spoken to the owners of an address after reports a person had travelled there from London.
SNP Westminster leader Ian Blackford MP said the aide's position was "completely untenable".
"What I find interesting.is that (according to some reports) members of Downing Street knew about this so, first and foremost, Boris Johnson has serious questions to answer over what now appears to be a cover-up". "Number 10 needs to provide a very swift explanation for his actions", Labour said.
Similar examples of public officials ignore lockdown guidelines have led to resignations and condemnation from senior Tories. A spokesman for the Labour Party told the BBC: "The British people do not expect there to be one rule for them and another rule for Dominic Cummings".
Mr Cummings was reportedly again seen at his parents' house on 5 April by a neighbour, who overheard ABBA's Dancing Queen playing loudly from the property as they passed on their regular exercise route.
Cummings would not be the first public official in the United Kingdom that has had to resign or lose their job over flouting lockdown rules.
"Dominic Cummings should have done the right thing, he should have resigned but now that he hasn't, Boris Johnson must show leadership and he must remove him from office immediately", he said.
He is one of several senior United Kingdom officials who have been accused of flouting the lockdown rules that they advocated for the rest of the country.
"He has known about this for six weeks". "It's as simple as that", Ed Davey, the acting leader of the Liberal Democrats said, according to the Guardian.
At the time - and as remains the case - those with symptoms of coronavirus are told to self-isolate at home and not leave even for essential supplies, if possible, for seven days.
British Prime Minister Boris Johnson's closest adviser travelled more than 400 kilometres from his London home after showing symptoms of coronavirus, breaking the government's lockdown rules, the UK's Guardian and Mirror newspapers reported on Friday.