The fate of more than 200,000 seafarers who play a crucial role in keeping global trade flowing is being labelled a "humanitarian crisis at sea".
More than 300 firms and organisations are urging for them to be treated as "key workers", so they can return home without risking public health.
More than 90% of global trade - from household goods to medical supplies - is moved by sea.
But governments have banned crew from coming ashore amid Covid-19 fears.
Large firms including shipping titan AP Moller-Maersk, oil firms BP and Shell, consumer giant Unilever and mining groups Rio Tinto and Vale, as well as maritime transporters, unions, the World Economic Forum (WEF) and other supply chain partners have signed the Neptune Declaration on Seafarer Wellbeing and Crew Change.
They are calling for all countries to designate seafarers as key workers and implement crew change protocols.
The signees of the Neptune Declaration are warning global leaders that ignoring the risk to crews' mental and physical wellbeing threatens global supply chains, which are crucial to vaccinating the world from coronavirus.
The firms and organisations hope that world leaders, gathering at this year's virtual Davos Forum, will heed their call.
"Unified, prompt action from governments and other key stakeholders is needed to protect the lives and livelihoods of the 1.6 million seafaring men and women who serve us all across the seas, and who continue to face extreme risk to their safety and earnings," said WEF's head of supply chain and transport Margi Van Gogh.
"By granting stranded seafarers key worker status, and by prioritising vaccine allocation for transport crew, we can prevent a deepening humanitarian and economic crisis."
Risk to mental and physical wellbeing
According to latest data from the International Chamber of Shipping (ICS) and international ship owners body Bimco, there are 1.6 million seafarers serving on internationally trading merchant ships worldwide.
Typically, ICS estimates around 100,000 seafarers are rotated every month, with 50,000 staff disembarking and 50,000 crew embarking ships to comply with international maritime regulations, governing safe working hours and crew welfare.
Seafarers usually work 10-12 hours shifts, seven days a week to man ships, on four or six-month-long contracts, followed by a period of leave.
But due to the coronavirus crisis and travel bans brought in by many governments to combat new variants of Covid-19, hundreds of thousands of crew are spending extended periods at sea, far beyond the expiry of their contracts.
For those who have been at sea for months longer than their contract stipulates, there is a growing risk to their mental and physical wellbeing.
"Seafarers are the unacceptable collateral damage on the war on Covid-19 and this must stop," said ICS secretary general Guy Platten.
"If we want to maintain global trade seafarers must not be put to the back of the vaccine queue. You can't inject a global population without the shipping industry and most importantly our seafarers. We are calling on the supply chain to take action to support seafarers now."
This article originally appeared on BBC News