Confirming the withdrawal of a previous forecast for net profits of JPY46.7 billion (£359 million/$440 million/€399 million) in 2020, the company said COVID-19 was "causing a slowing in demand across our industry."

It added: "We are not immune.

"This has put pressure on our performance in Japan and the international business."

Dentsu said it had taken "swift cost actions to mitigate this revenue decline, protect margin and safeguard our people’s jobs.

"However the current business environment continues to be severe.

"Given this situation, the second quarter {April to June} is expected to be the weakest quarter of the year."

Cost-cutting measures implemented since February are said to have included "stopping all non-essential travel and discretionary spending, an immediate review of contractor roles and arrangements" and "pausing of all [mergers and acquisitions] activity until at least the end of [the current quarter]."

On the personnel side, Dentsu said that measures including reduced working hours and temporary salary reductions were implemented among its 66,000 employees.

In spite of current difficulties, the group reported a year-on-year improvement in first-quarter performance, with revenue edging up 0.9 per cent to JPY252.7 billion (£1.9 billion/$2.4 billion/€2.16 billion) and operating profit advancing almost 35 per cent to JPY37.2 billion (£286 million/$351 million/€318 million).

Dentsu President Toshihiro Yamamoto said the organisation's new business teams had adapted quickly to "hosting, and winning, pitches virtually."

Dentsu was, he said, "supporting our clients to ensure they can emerge even stronger post crisis by providing rich consumer insights and adapting our services to support their evolving needs."

Dentsu was appointed as the exclusive Olympic and Paralympic marketing agency in Japan a year after Tokyo was awarded the now postponed Games in 2013.

The company has also enjoyed a longstanding commercial relationship with World Athletics.