Dominic Cummings made a second trip to Durham during the lockdown, according to reports.
The prime minister's top aide was seen on 19 April near his family's home in the North East, said The Guardian and the Daily Mirror.
On 14 April, he had been photographed in Downing Street after he had returned from Durham.
In the latest allegations, the Mirror reported he had been spotted in woods near the family's Durham property on 19 April.
In late March, Mr Cummings allegedly broke lockdown rules when he travelled 260 miles from London to Durham with his wife and son to stay with his elderly parents – after the aide developed coronavirus symptoms.
Mr Cummings said he wanted help from his family caring for his young son if he and his wife became too ill to do so alone.
Durham Police confirmed they spoke to the owners of a property on 31 March – a week after the prime minister imposed the lockdown – after a call from someone reporting they had seen Mr Cummings in the area.
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But Downing Street said nobody related to Mr Cummings was spoken to by police, and it was entirely right for him to seek childcare for his four-year-old son.
Mr Cummings has insisted "I behaved reasonably and legally".