Stores including B&M, Card Factory, Smyths, Halfords Boots, Marks & Spencer and Currys PC World closed today due to the torrential rain.
It follows Portsmouth being battered by lightning, heavy rain, and strong winds in the early hours of this morning, with streets across the city deluged with rainwater.
Several stores at the Burrfields Road site have now partially or full reopened.
According to a message posted on social media by the retail park, M&S and Cardfactory had hoped to reopen by 3pm.
Currys PC World and Boots are unlikely to reopen today.
Halfords and Smyth have opened the fronts of their stores for click and collect services only.
B&M has partially opened the store, with limited isles opening.
In the social media message, a representative for Ocean Retail Park said: ‘We apologise for any inconvenience caused and will keep you continue to keep you updated with their opening times.’
Roads across Portsmouth saw flash flooding after heavy rainfall on Sunday night, with Northern Parade among the worst affected.
Showers are expected to continue today and then return on Friday.