Two visitors were asked to leave the house of Rob Roberts, MP for Delyn in north Wales, and balloons and banners were seen outside, according to The Mirror.
Superintendent Mark Pierce, from North Wales Police, told the newspaper officers were called to his address on Monday.
He said: "In response to two reports of a possible breach of Covid-19 regulations, we visited an address at Ty'n y Coed, Mold, yesterday (Monday, May 25).
"When we called at the property, two people visiting the house left following advice and no further action was taken."
A spokesman for Mr Roberts said: "Rob Roberts was not present at the time.
"His family have been reminded of the guidelines set out by the Government."
In a Facebook post on Monday, Mr Roberts backed Boris Johnson's embattled adviser Dominic Cummings, who is facing calls to resign over allegations he breached lockdown rules.
Following Mr Cummings's news conference, the MP said: "I believe that he seemed to be entirely acting in the best interests of his child as a responsible husband and father."
In a previous social media post earlier on the same day, Mr Roberts said there were "many questions" about Mr Cummings's actions that must be answered.
"Of course it is right that we cannot have one rule for one and another for the rest," he wrote.
"I have asked for a proper investigation into the situation and whatever the outcome that should be the end of the matter.
"If Mr Cummings has acted inappropriately according to an investigation, then he should go."