PORTLAND, Maine (NEWS CENTER) -- One of the key issues on the Maine ballot is about raising the minimum wage. Question Four would increase the minimum wage to $12 an hour over the next four years.

But another part of it would eliminate the special “sub-minimum wage” for workers who earn tips' also known as the tip credit.

At Vena’s Fizz House restaurant in Portland, the Yes on 4 campaign said Wednesday it is putting that tip credit issue front and center during the final days of the campaign. Supporters said many bartenders and servers have a hard time earning enough money with the reduced hourly wage.

But a short distance away at DiMillo’s restaurant , several servers said they can make good money with the current system, and don't want it changed. Owner Steve DiMillo said the higher labor costs created by the referendum would be a major problem for many Maine restaurants.

Fizz House owner Steve Corman said it will be better for workers and won’t hurt the restaurants.

"It's working in seven other states," said Corman. "It's working for the workers in those states and the owners of those bars and restaurants why shouldn’t it work in Maine also?"

But DiMillo said his servers make a good hourly wage. He said raising wages for non-tipped workers is a good idea.

"I’m not in opposition to that, he said. "I’m in opposition to eliminating the tip credit. We’re for increasing the minimum wage."

If Question Four passes, it would phase out that tip credit over seven years, starting in 2017 with an increase is the sub-minimum wage to $5. It would reach the same $12 level as the regular wage in 2024. But some legislators have already talked about trying to repeal the tip credit portion of the law if it does pass. And some restaurant industry leaders have encouraged the idea.