Services of the cross-Channel train have dropped to just one train a day between the British and French capitals amid tightened border controls.
British business leaders are calling on the UK government to provide financial help to Eurostar, stressing the COVID-hit rail link to Europe is "in peril".
In a joint letter to UK finance minister Rishi Sunak and transport minister Grant Shapps, leaders from 28 UK businesses called for "swift action to safeguard" Eurostar's future, which they say could run out of funds in the coming months.
The railway company has also renewed its call for British funding, warning that "there is a real risk to the survival of Eurostar".
The cross-Channel train has suffered a 95 per cent drop in demand since the beginning of the health crisis as lockdowns and border control measures have hampered travel.
Both the French and British governments have in recent weeks tightened border controls with travellers required to show a negative COVID-19 test and to quarantine upon arrival. The measures were in response to the spread of new variants of the novel coronavirus, which were found to be up to 70 per cent more transmissible.
Currently, Eurostar operates just one service a day between Paris and London.
London First, the business lobby which wrote the letter to the British government on Sunday, argued that "with international passenger numbers likely to remain low into the spring, our green gateway to Europe is in peril".
"If this viable business is allowed to fall between the cracks of support – neither an airline, nor a domestic railway – our recovery could be damaged," it added.
"Eurostar is not asking for special treatment. We urge you to ensure that they have equal access to financial support as companies in similar positions – at the very least this should include business rates relief and access to Government loans".
Eurostar, which is majority-owned by France's state-owned rail company, SNCF, is believed to have tapped into all financial assistance available to them from the French government. But it has received nothing from the British government which has allocated £3.5 billion (€3.93 billion) and £1.8 billion (€2.02 billion) to its domestic railways and commercial aviation respectively.
In a statement, also issued on Sunday, the company said it is "encouraged by the government backed loans that have been awarded to airlines and would once again ask that this kind of support be extended to international high-speed rail which has been severely impacted by the pandemic".
"Without additional funding from government there is a real risk to the survival of Eurostar, the green gateway to Europe, as the current situation is very serious," it added.
WATCH:Business analyst Guy Shone says part of the challenge is that many people see Eurostar as a French company: