The Consumer Product Safety Commission unanimously agreed yesterday to postpone indefinitely any mandatory rules to require manufacturers to make upholstered furniture more resistant to fires, especially those started by smoldering cigarettes.

The decision gives the industry the go-ahead to continue its 2-year-old voluntary program to make furniture more flame-resistant. Although the program has not been as successful in reducing furniture fires as some agency officials had hoped when they approved the voluntary approach two years ago, the CPSC commissioners said the industry has taken an important first step in making its products safer.

What's more, they noted, the industry promised to try to halve the number of deaths that occur each year from upholstered-furniture fires.

The problem, said Commissioner Stuart M. Statler, no longer lies with the furniture makers but rather with the cigarette companies, because they have failed to develop a self-extinguishing cigarette. Smoldering cigarettes are the major cause of the 39,000 upholstered-furniture fires each year which cause 3,700 injuries and 1,500 deaths.

The decision to let the furniture industry continue its voluntary program comes after more than five years of CPSC efforts to develop a mandatory rule.

However, noted Commissioner R. David Pittle, "I shall sadly but unhesitatingly vote to direct the staff to submit its draft mandatory standard" if the number of furniture fires is not reduced.