Dennis Williams, leader of the United Auto Workers union, was present at the union's national bargaining convention in Detroit on Wednesday.

He has rejected a tier of lower wages for workers making auto parts. Williams affirmed that the union already has too many tiers of low wages. He was responding to the reports revealing that General Motors Co. and Ford Motor Co may propose a third tier of pay.

Williams is facing pressure from union members to send a second tier of wages. He affirmed that he has come across talks about the third tier in which employees would be paid less than the $15.28 starting salary for second-tier workers.

It is said that third tier of wages are already active in many factories of General Motors in the Detroit area. The tier is active for workers who build battery packs and place parts to be assembled on cars.

Williams wants that gap in wages should be covered, but he also agrees that they are present in situation where they are competing in a global economy. At the convention, many have spoken in the favor of pay raises for veteran workers.

It's been a long time that UAW workers have not had any hourly pay raise. But they have received significant amount of profit-sharing checks. In his speech, Williams did not mention to have the salary raise, but in the past he does have said that there are ways by which raises can be given and the companies can be kept competitive.

The convention takes place after every four years. This year's talks are the first one after the auto industry has fully recovered from the recession. It could also be turn out as a controversial one, as the union is seeking a share from the industry's revenue.