Admin workers scaled up from four to 80 as claimants say the process takes too long and does not pay out enough.
Increasing demand for Covid vaccine injury payments has seen the number of staff processing claims increase 20-fold, figures show.
The Vaccine Damage Payment Scheme (VDPS) has scaled up operations and boosted its administrative staff from four to 80 to handle the claims.
A project is also under way to digitalise the application process to make it simpler and quicker for claimants.
But MPs, campaigners and families have called for the process to be reformed, arguing that the payment cap of £120,000 is too low, too slow and bureaucratic, and the eligibility criteria is too strict.
If a person is left severely disabled as a result of receiving certain vaccines they could be entitled to the one-off payment from the Government.
Families can also apply for the payment if a loved one died as a result of a vaccination.
It is not treated as compensation, meaning claimants can still seek damages in court.