AMCU members have already voted in favour of a stoppage at Impala Platinum over wages and the union will canvas its rank and file this week at Anglo American Platinum and Lonmin.
The three are the world's top producers of the precious metal and account for over half of global output.
AMCU President Joseph Mathunjwa told reporters a decision would be made next week.
"Yes, there will be a strike, if our members give us the go-ahead we won't hesitate to do that. AMCU is not a company, it doesn't have a board of directors. We get a mandate from our members," he said.
At Amplats and Lonmin, the union is seeking a minimum monthly wage of 12,500 rand for entry-level workers - more than double current levels. AMCU says that would be a "living wage". At Implats the union scaled back its demand late last year to just over 8,500 rand.
AMCU has emerged as the dominant union on South Africa's platinum belt over the past two years after wresting tens of thousands of members from the once unchallenged National Union of Mineworkers (NUM) in a violent turf war in which dozens of people were killed.
The union also has thousands of members in the gold sector who have rejected wage increases of 8 per cent agreed last year by NUM.
Mathunjwa said its members could also down tools at bullion producers such as AngloGold Ashanti.