The South Wales Argus reports the Cambrian Centre redevelopment from Scarborough Development Group will house commercial property, retail units, parking space and a food store.
But director Mark Jackson is said to be worried about councillors' decision to grant permission for an out-of-town Morrisons supermarket in Lliswerry.
"National and local policy has recognised for many years [that] out-of-town retail development can badly damage the vitality and viability of town centres," Mr Jackson was quoted as saying.
His firm's £40 million plan is said to be a "key regeneration site" and could bring 800 new jobs to the area.
A spokeswoman from the Welsh Assembly said people could call the planning application in for discussion, but ministers decide whether or not to do so, the publication added.
Morrisons states it already has more than 403 UK stores and is looking to expand in new locations.
Posted by Sarah Smith