Sinn Fein has criticised B&Q for putting an Olympic emblem, which includes a Union Jack, on its uniforms.
B&Q is sponsoring the British Olympic team
The DIY chain, which is sponsoring the Great Britain Olympic team, said individual workers could decide whether to wear the new work clothes or not.
However, Ms Ruane claimed those who chose not to could be subjected to "sectarian intimidation".
She said she had been contacted by "a number of staff members" who are unhappy about the uniforms.
"This decision is short-sighted and displays an ignorance of the very
divisive nature of symbols in the north," the South Down assembly member said.
However, the DUP's Ian Paisley junior backed B&Q over the issue.
"I welcome the fact that B&Q are standing by their decision on this. I think it only reflects on Catriona Ruane," he said.
"Coming up to our Olympics in London, this is the sort of thing which has to be welcomed and encouraged."
A spokeswoman for B&Q said they were proud to support and sponsor the Great Britain and Northern Ireland Olympic team.
"All B&Q staff have the option of wearing this workwear or their normal B&Q uniform and every employee has complete freedom of choice in this matter," she said.