Cabinet Office minister Michael Gove had to abandon a meeting with Nicola Sturgeon and other leaders of the devolved nations on Thursday after a coronavirus alert.
The chancellor of the Duchy of Lancaster was notified he may have come into contact with someone who had coronavirus on a trip to Portugal through the NHS app.
The Daily Mail reported that it is believed the contact happened on the flight home from Porto.
He had travelled with his son to watch the Champions League final between Chelsea and Manchester City.
The Cabinet Office confirmed Gove had been pinged by the app.
Gove had been due to meet the first ministers of Wales, Scotland and Northern Ireland with the prime minister in a bid to strengthen the union.
Instead of self-isolating for 10 days, Gove will be able to take part in a pilot scheme for workplaces, including No 10, where he can instead be tested every day for a week.