The Hall for Cornwall (HFC) is set to close for more than a year while a £17 million refurbishment programme is carried out.
The theatre in Truro wants to redesign the auditorium, with the addition of 250 seats, as well as build a new foyer and entrance, including cafe and bars.
Cornwall Council, which owns the Grade II listed building, met yesterday to consider giving £3 million towards the project, with a final decision due next month.
A report compiled for the Council says HFC has been running “a break-even subsidised business model” and needs to increase annual profits by at least £400k to remain competitive.
The proposed increase in seating could boost annual profits “by about £450k”.
The redevelopment work is scheduled to start in late 2017, with the venue closing for up to 15 months.