BBC reported Saturday that unions have called for a monthly minimum salary of $450.
In response, Tsvangirai said no government worker, including President Robert Mugabe, was earning more than $100 a month.
"This government is broke, and we are only able to pay the $100 allowance," Tsvangirai was quoted as saying.
He added that the wage would "graduate into a proper salary" when the coalition government's financial situation improved.
"We have been in office for less than three months. I plead with you to please give us time," he said.
Lovemore Matombo, president of Zimbabwe's Congress of Trade Unions, has said state workers are prepared to strike if their demands are not met. He has not given a deadline.