One of the region's largest zoos has called on the government for more clarity about a £100m rescue package for zoos.
Zoos will be able to bid for a share of the £100m pot, the Department for Environment, Food and Rural Affairs (Defra) announced on Saturday, 27 June.
However, the owners of Whipsnade Zoo, ZSL, said they "ugently" needed to know how much money they might have access to.
A statement from ZSL added: "While ZSL welcomes all financial support for zoos, ZSL was deeply disappointed that it was effectively ineligible for the earlier zoo support scheme announced by the Government; we urgently call upon DEFRA to set out the details of the expanded scheme to confirm that support of the scale required will be made available."
In a statement responding to Whipsnade's call for more detail, Defra said any zoo which holds a license would be able to apply for a share of the funding, but did not reveal how much money would be available to them.
Zoos have been able to reopen since June 15, but many are predicting heavy losses due to the coronavirus lockdown.
ZSL, who also run London Zoo, are forecasting losses of £20m across the two sites this year.
Lord Goldsmith, the minister for Animal Welfare, said the new fund would help those zoos struggling to balance their books.
He said: "Allowing zoos to reopen has taken off some of the pressure, but the coronavirus pandemic has left them facing long-term financial problems.
"This funding will therefore be a lifeline for our zoos and aquariums and ensure the quality of animal care continues over the coming months."
The Zoological Society of East Anglia (ZSEA), which runs Banham Zoo in Norfolk and Africa Alive in Suffolk, welcomed the funding but highlighted the lack of detail about eligibility in the original announcement.
Claudia Roberts, Managing Director of ZSEA, said: "The Defra announcement of a £100 million rescue package is welcome news although the details about how to apply or which zoos are eligible have not yet been given.
"We have incredible fundraising support from our communities and we are reopening to the public on July 4, but we still have a huge mountain to climb to survive over the long winter period ahead."