Video report by ITV Wales correspondent Carole Green
The Prime Minister has failed to answer questions on allegations about his conduct while on a visit to a factory in Wrexham.
Over the last few days, a number of allegations have emerged about Boris Johnson, following conflict between him and his former chief aide Dominic Cummings.
Overnight, claims emerged that Mr Johnson would rather have “bodies pile high in their thousands” than implement a third coronavirus lockdown.
He denied making this comment but refused to answer when asked whether his presence on in North Wales was damaging to the Conservatives' efforts ahead of the election.
When asked about whether his presence on the campaign trail ahead of the Senedd election on 6 May could do more harm than good, the Prime Minister told ITV News, "I think that what people want to hear about is our plans to unite the level up across the whole of the country.
"And what they're interested in, is whether we have a vision we're here in North Wales, whether we have a vision for the North Wales Economic Corridor, which we do."
One of the allegations about Boris Johnson is that the refurbishment of his flat was being funded by Conservative Party donors. International Trade Secretary Liz Truss said the PM paid for the work "from his own pocket," but refused to say whether Mr Johnson had received the money from a Tory donor.
Mr Johnson told ITV News that "anything to be said about that... will be declared in due course."
The Conservatives will be hoping to make similar gains in north Wales which were seen in the last General Election.
Although the latest poll for ITV Wales projected that the Labour Party could keep the so-called Red Wall seats that were lost to the Conservatives in 2019.
Boris Johnson visited the area on Monday as the Conservatives announced plans for the region. They said they would introduce a dedicated minister for North Wales and deliver more community hospitals in the area.
The Prime Minister did not commit to giving Wales the extra resources to deliver such pledges if another party wins the election.