The aerospace engineering firm, formerly known as Maydown Precision Engineering, went into administration earlier this month.
The other 50 staff are due to return to the factory floor on Wednesday afternoon.
Liam Gallagher from the Unite union said their future is still uncertain.
"Thirty workers will be made redundant and unfortunately those workers will have to seek that statutory redundancy," he said.
"The other workers will be returning to work this afternoon to fulfil outstanding contracts and obviously we are deeply concerned about the prospects for those workers.
"Obviously there is absolutely no guarantee beyond the existing contracts that are there."
Administrators were called into Schivo NI, formerly known as Maydown Precision Engineering (MPE), a supplier to major aircraft manufacturers such as Bombardier.
MPE was bought by the Waterford-based Schivo Group two years ago.
A spokesperson for the company said the group had been "unable to turn around Schivo NI Ltd".
In August 2015, the workers union, Unite, voiced concerns over possible job losses.
The company had previously said it would be expanding its interests in the aerospace engineering sector.
The Schivo Group has business interests in the medical technologies, aerospace and oil and gas sectors.
A trade union has said 30 workers have been made redundant at the Shivo factory in Londonderry.