TORONTO - Finance Minister Jim Flaherty is said to be putting the final touches on a "voluntary code of conduct" to govern Visa's and MasterCard's entry into Canada's $168-billion debit card market.

The Toronto Star reported Saturday that Flaherty is expected to announce the measures in the weeks ahead as a complement to his new credit-card regulations.

It said the code of conduct will tackle such thorny issues as the priority routing of debit transactions over Visa's and MasterCard's networks; the use of so-called "dual-purpose cards" that have both debit and credit functions; and increased transparency around rates and fees.

While the code is likely to call for "a more definitive" fee schedule, the newspaper said Flaherty is expected to steer clear of imposing caps.

Critics complain a non-binding code will offer no protection to retailers and small business owners.

They fear processing fees will soar once Visa and MasterCard debit cards are in wide circulation.