The outlook for Sydney's CBD dining is so bleak the restaurateur behind one of the largest clusters of independent restaurants in the city is handing back the keys to his landlord and surrendering his once-prized nine-year lease.

Peter Petroulas won't reopen his GPO Grand food stable, where 150 staff worked across Intermezzo, the Italian restaurant populated with city executives, high-end steakhouse Prime, a cheese and wine room, Spanish restaurant and city sushi train Sosumi.

Surrounded by sparsely populated hotels and office towers, the veteran restaurateur maintains most of the businesses his restaurant feeds off don't plan to bring staff back en masse until next year. He argues it'll be too late for his two-decade-old restaurant group.

"Those who want to come back to work have to try and get on buses with limits, get on lifts that can only take four people at a time. There's not going to be a solution any time soon. I think the suburbs will be OK, but it's a different situation for hardcore CBD operations," Petroulas says.

"We've had our revenue closed down but haven't had our costs completely closed down," he adds.

Petroulas says city restaurateurs are walking into a perfect storm when you couple difficult trading conditions with even a percentage of back rent still owing.

Despite having business interruption insurance, which he says is being withheld, Petroulas says "you don't plan for this".

"I've spoken to the landlord and they've allowed me to surrender my lease on July 31," he says.

It'll put a full stop on Petroulas' 18-year run at GPO.