By Andy Bruce

LONDON, March 20 (Reuters) - Britain will take further desperate measures to stem the collapse of its economy on Friday, when finance minister Rishi Sunak will outline plans to prop up companies and workers who face hardship from the coronavirus outbreak.

Sunak has been meeting trade unions and industry associations, who have warned that mass lay-offs are imminent unless help can be found within days rather than weeks.

As the coronavirus outbreak sweeps across the world, governments, companies and investors are grappling with the biggest public health crisis since the 1918 influenza pandemic.

Sunak is now considering tax holidays for companies and reversing the pay-as-you-earn tax system to funnel directly cash to companies so they can keep paying staff, the Financial Times reported.

"We are working at pace, urgently, to see what further support we can put in place, particularly around employment support, looking at some models elsewhere and looking at what model might work best for workers here today," Sunak told lawmakers in parliament's Treasury Committee on Wednesday.

The 39-year-old has adopted "whatever it takes" as his refrain, borrowed from former European Central Bank President Mario Draghi whose use of the phrase helped to quell a debt crisis in the euro zone.

In the five weeks since he became finance minister in a shock promotion, Sunak has announced a budget which included a 30 billion-pound stimulus plan and this week has launched 330 billion pounds ($380 billion) of loan guarantees for business.

But these measures failed to restore confidence in the world's fifth-biggest economy.

The pound crashed to its lowest level against the dollar in 35 years on Wednesday and British government bond prices plunged as scores of companies, big and small, said they would need to cut jobs to survive.

These factors spurred the Bank of England into cutting interest rates to 0.1% on Thursday and unleashing an extra 200 billion pounds of bond purchases.

Asked on a BBC panel show what Sunak would announce on Friday, health minister Matt Hancock said: "All I can say is mark my words -- we are going to do everything we can to keep people supported at times like this." ($1 = 0.8679 pounds) (Reporting by Andy Bruce, editing by Estelle Shirbon)