The ICS said James Paget Hospital’s bed occupancy rate was already at 95% capacity while that at East Coast Community Care was 98%.
It said: “If we are unable to secure these contributions and expand our estate infrastructure then the impacts would be unsustainable and the ICS would have to object to the proposed planning application.”
It is asking Repton Property Developments pay £506,355 to help healthcare services cope with the increase in the population.
The scheme has also proved controversial with people living nearby, according to the Local Democracy Reporting Service.
Bradwell Parish Council has objected to the scheme, stating the “impact on the village is significant”.
Other objectors have called the plans “absolutely ridiculous” and said “there isn’t the infrastructure to cater for so many residents”.
It is estimated the development could grow the area’s population by about 980 people.
Great Yarmouth Borough Council is expected to make a decision on the plans in the spring.