Bosses at restaurant and food chains including Wagamama and Pizza Hut have warned the prime minister the sector faces mass job cuts without more help.
In a letter to Boris Johnson backed by 90 firms, they say that if social distancing remains they will need action on tax, rents and other support.
Without more help, the sector faces "grave damage", the firms say.
Deliveroo organised the letter, signed by its partner restaurants including Itsu and Pret A Manger.
The companies, which together represent more than 1,000 outlets, praised government measures already introduced, but said more "swift action" was needed while two-metre separation requirements remained in place.
The government has commissioned a comprehensive review into the two-metre rule, which the prime minister's official spokesman said on Monday would "look at evidence around transmission of the virus in different environments, incidence rates and international comparisons". Ministers have said the review will be completed "in the coming weeks".
In the letter, the bosses write: "Without government support to help restaurants to generate revenue and cover costs, tens of thousands of restaurants may be forced to permanently close their doors in the coming months.
"This crisis is far from over and the potential consequences are deeply concerning. A huge number of restaurants across the country are facing the prospect of bankruptcy."
The firms own outlets across the UK, but are likely to reopen them at different times. In Northern Ireland, restaurants and cafes can reopen from 3 July, and in England the day after. The Scottish government has outlined a phased approach to pubs and restaurants reopening but there is no date. Nor is there a date for Wales.
- Julian Metcalfe, founder and chief executive of Itsu
- Pano Christou, chief executive of Pret A Manger
- Emma Woods and Nigel Sherwood, chief executive and chief operating officer of Wagamama's
- Neil Manhas, general manager for Pizza Hut UK.
The action called for includes slashing VAT on restaurant food and maintaining the Job Retention Scheme for restaurants while social distancing measures are in place.
The chains also want "mortgage holidays" for landlords, so that this can be passed on in the form of lower rents, and an extension of the moratorium on evictions for as long as social distancing measures prevent restaurants from operating at full capacity.
A government spokesperson said: "We are working closely with the hospitality sector to develop safe ways for restaurants, bars and cafes to reopen as soon as we can from July.
"These businesses can continue to access our extensive package of support, including our job retention scheme which has been extended until October - meaning it will have been open for eight months and will continue to support businesses as the economy reopens and people return to work."
The spokesperson also pointed out that this was in addition to 100% business rates holidays, loans and tax deferrals.
Many restaurant chains were in trouble before the coronavirus lockdown, which has only exacerbated the pressures. Last week, the owner of Frankie and Benny's, The Restaurant Group, became the latest big name to restructure, announcing 3,000 job cuts and 125 closures.
A recent survey by Deliveroo found more than half of small and independent restaurants said they would have to close within three months without further support.
"Without government support to help restaurants to generate revenue and cover costs, tens of thousands of restaurants may be forced to permanently close their doors in the coming months," it said.
The signatories pointed out that last year, customers spent £40bn in restaurants, supporting one million employees.
Kate Nicholls, chief executive of industry trade body UK Hospitality, said: "Household name brands on every High Street have been closed and many will be operating at well below capacity once lockdown ends.
"As these proposals from Deliveroo and their partner restaurants show, restaurants need urgent support from the government so that they can help rebuild economies and give people some much-needed enjoyment. Without it, some will close permanently and people's jobs will be lost."