The mall, the city's main pedestrian shopping thoroughfare, has some of the city's most sought-after retail real estate - commanding correspondingly steep rents - and is home to flagship department stores Myer and David Jones.

The lure of shoppers flocking to Bourke Street made it the location of choice for well-resourced international fast fashion brands H&M and Zara when they established their first Australian stores several years ago.

But soaring rents and tougher trading conditions are giving some local retailers second thoughts.

Fashion retailer General Pants Co is understood to be looking to exit the mall despite trading for just two years on a 10-year lease in a prime position next to retail goliath David Jones.

The multi-brand retailer founded in Sydney 45 years ago has approached estate agents, looking to give up its position in the mall and assign its lease to another retailer.

It echoes a move the company made last week when it gave up its location in Sydney's premier shopping strip, Pitt Street, for another larger outlet in nearby George Street.

Further along Bourke Street, another local owner-operated retailer Thomas Jewellers has also decided to close its store.

The strata-titled Thomas Jewellers shop, part of the heritage listed Royal Arcade building, will be re-leased through Cushman & Wakefield.

A twin shop, on the opposite side of the arcade's entrance occupied by a BankWest branch, was recently listed for sale with a $30 million price tag. It failed to find a buyer.

Another prominent fashion retailer Cotton On, also just 18 months into a long-term lease on the mall, is understood to be reconsidering its location.

Cotton On's shop, in the London Stores building opposite H&M, is owned by Pacific Group.

Chief executive Graham Terry said there "were no issues" with leasing arrangements in the building.

"Overall retail is a bit challenging. It's right across the board. The economy is tightening up a bit. I don't think it's just Bourke Street Mall," Mr Terry said.

Despite some retail hardship, the mall still has some of Melbourne's most sought-after real estate.

Danish jewellery giant Pandora is the latest in a long list of international brands to open a flagship store in the mall, recently signing a million-dollar lease on a four-storey gothic-style brick building next to Zara.

The Copenhagen headquartered jewellery brand is understood to have taken a lease for nearly $1 million in annual rent at 280-282 Bourke Street.

Shops on the strip regularly attract rents between $8000 to $10,000 per square metre with prominent corner spaces signing tenants for up to $11,000 per sq m.

Consumer habits have changed with shoppers more focused on mobile technologies and internet purchases, Australian Retail Association director Russell Zimmerman said.

"People are spending differently to what they once were," he said.

"We're not seeing growth in fashion. There is stronger competition from other retailers and more and more shopping centres are putting in food rather than fashion."

Potential disruption from works on the $11 billion Metro Rail tunnel project on Swanston Street may also prove an ongoing headache to city retailers.

Demolition works are expected to ramp up along the city's central core over the next few months.