Mofaz held a closed-door meeting Tuesday; however, he has yet to make an official announcement, the Jerusalem Post reported.
The standoff between the Kadima and Likud parties over the Tal Law came to a head after Prime Minister Binyamin Netanyahu submitted a proposal early Tuesday to equalize the burden of military service.
Haaretz reported the proposal would require 50 percent of ultra-Orthodox Haredim Jews to enlist in the armed forces between the ages of 18 and 23. Another 50 percent would be able to enlist in operational civil services, such as the police force or the prison service, between the ages of 23 and 26.
"Netanyahu's proposal contradicts the ruling of the High Court of Justice, does not conform to the principle of equality, is disproportionate and does not meet the tests of effectiveness that are set down in the High Court's ruling or the principles of the committee on equalizing the burden of [Israeli Defense Forces] service," Mofaz said Tuesday.
"Let's make this clear: We are referring to enlistment targets that do not include all of those eligible for the draft, and we are therefore countenancing a 'word-laundering' that in effect leaves the situation as it was," he added.
Meanwhile, the Knesset is to vote Wednesday on a simpler version of a draft bill, which would draft all 18-year-olds into armed service.