Councillor Gerald Vernon-Jackson insisted the Bonfire Night display at King George V Playing Field, in Cosham, next week would not be cancelled.
The city leader’s comments come amid speculation over the showcase’s immediate future following moves by other cities to pull the plug on their displays.
Manchester City Council last week announced it was scrapping all its eight major events due to ‘unworkable’ Covid status checks.
Meanwhile, a similar move was announced in Leeds, which cancelled its six shows for the second year running over fears they could become a ‘super-spreader’ coronavirus events.
Portsmouth’s infection rate in recent weeks has soared and is now significantly higher than both Manchester and Leeds.
Data released on Wednesday showed 521.1 people per 100,000 of the population were infected with Covid-19, compared to 317.1 in Manchester and 466.6 in Leeds.
However, despite this, Cllr Vernon-Jackson was confident the city could ‘on the balance’ of things still safely stage the event on Wednesday.
The council leader said: ‘Other cities like Manchester and Leeds are closing their displays down – people don’t do that lightly.
‘Our Covid rates are going up fast and we have got to be careful but on balance we think it’s right to still go ahead.
‘We sat down and questioned whether we should run it or not. We sometimes get to 10,000 people attending. But it’s in open air and people can wear masks if they choose to.
‘People deserve to be able to celebrate.’
The event on Wednesday opens from 4pm, with the Bonfire being lit at 6.30pm following by a stunning fireworks display at 7.30pm.
Portsmouth City Council has previously said it will be following government guidelines to ‘keep the event safe’.
All those attending are urged to take a lateral flow test within 48 hours of the display and to wear a face covering if using public transport or walking through the underpass to the playing fields.
Those displaying symptoms of Covid-19, have been asked to self-isolate or have tested positive for coronavirus in the last 10 days are also being urged not to attend the function.
The show will be the first time since 2019 that Portsmouth has been able to hold it’s annual fireworks bonanza at King George V.
Councillor Ben Dowling, Portsmouth’s culture and leisure boss, hoped the spectacle would go off with a bang.
He added: ‘I’m delighted to see the return of our annual bonfire and fireworks display following last year’s cancellation due to Covid-19 restrictions. This is an event enjoyed by people of all ages, and I hope everyone has a wonderful evening.’