Party members are to choose a candidate on July 27.
Former premier Jim Prentice won the riding in the May 5 provincial election but quickly resigned when the Progressive Conservatives were swept from power.
So far the people who want to be the New Democrat candidate include Anne Wilson, who lost to Prentice, and former NDP MLA Bob Hawkesworth.
Hawkesworth also served on Calgary city council for 23 years.
No date has been set for the byelection, which must be held before the end of the year.