Lavang in Nether Green is seeking planning permission from Sheffield Council to put down wooden decking at the front of its premises to provide extra space for customers.
The Indian restaurant wants to offer the outdoor seating between midday and 11pm during warmer weather.
But 26 residents have submitted objection letters to the scheme citing a wide range of concerns from increased noise and traffic to vermin and smells emitted from the premises.
The objections are detailed in council planning documents and state: "Food may be able to fall between the gaps of the decking and may lead to vermin.
"The loss of the area of the forecourt would result in delivery vehicles parking on the surrounding streets which are already congested.
"The development would result in overlooking to neighbouring properties and gardens, resulting in a loss of privacy. The decking would be likely to be busiest during warm weather when local residents would be more likely to have windows open, exacerbating noise problems."
But Lavang's co-owner AJ Ali has insisted the restaurant would generally maintain its normal hours - Sunday to Thursday from 5.30pm to 10.30pm, and Fridays and Saturdays up to 11pm - despite the new request to start at noon.
He said: "We've applied for permission from midday to 11 just to give us that flexibility in case anyone wants some sort of party, or whatever it may be."
Planning officers have recommended the scheme for approval on the condition that the decking cannot be used outside the hours of noon to 9pm on any day.
The application will go before the planning committee at Sheffield Town Hall on Tuesday.