Rundle Mall retailers in Adelaide say holiday trading proved a success.

The city stores were allowed to open for the Tuesday public holiday, after also trading last Saturday.    

Rundle Mall Management Authority general manager Martin Haese says business approached the levels seen close to Christmas.

"I think the unanimous reaction to this is one of great, great satisfaction," he said.

"There would be close to 100,000 people ... this is unprecedented, people are voting with their feet."  

The State Opposition says Rundle Mall retailers should be allowed to trade on all non-religious public holidays.

MP Rachel Sanderson says there would be a number of benefits.

"I would like to see negotiations go further for the good of the state, particularly for the centre of our city, which is a tourist precinct and I think it would be a very sensible and wise thing to do in the future," she said.