By Marc Jones

LONDON (Reuters) - Credit rating agency Moody's is carrying out a global review of its corporate ratings in light of the coronavirus and oil price slump, with a first mass wave of downgrades or downgrade warnings likely in the coming days.

The firm has already begun the process in a number of the hardest hit sectors such as airlines, cruise and oil firms [nL4N2BC0DE] [nMDYF4P5p][nMDYdFHQT], but the moves are about to ratchet up, two of the firm's top analysts told Reuters.

"We are undertaking a global review of ratings that are impacted by the virus," Managing Director of Global Strategy & Research Anne Van Praagh and Christina Padgett, Associate Managing Director of Corporate Finance Research, said in an interview.

"By the end of the week we will have a fair amount of rating actions," Van Praagh added, saying it was likely to impact whole groups of companies or sectors all being impacted in the same way.

Earlier this week Moody's said that about 9% of the 920 companies it rated in Europe, the Middle East and Africa had a "high exposure" to the effects of the coronavirus outbreak, with another 54% having moderate exposure.

It also estimated that about 16% of the more than 2,000 companies it rates in North America would be at high risk of rating move under the now widely expected scenario of a global recession.

"We have the virus, the big fall in commodity prices and now (the pressure in) the capital markets. This combination of events is unprecedented, so we have to come at it from several different angles," Padgett said.

The first flurry of downgrades could take a few weeks. As well as sectors like airlines, oil and gas and travel, shipping, hotels and entertainment and leisure will all be heavily impacted too.

Firms with weaker finances already in the junk grade, of high yield category as it is also potentially see multi-notch downgrades, while on the flip side government support, if strong enough, could potentially spare others.

"Some of the bigger companies that are coming under pressure may benefit from extraordinary government support - in those cases, that may temper the rating actions," Van Praagh said

(Reporting by Marc Jones; Editing by Angus MacSwan)