The Majority Coalition Caucus announced Tuesday night that it planned a news conference Wednesday to announce the details of the plan.
Gov. Jay Inslee unveiled his proposal last week, laying out plans to make some temporary taxes permanent and to end some tax exemptions to address both the state's projected budget deficit and a court-ordered requirement to put more money into the state's basic education system.
Lawmakers are in the midst of a 105-day legislative session. They are tasked with patching a projected deficit of more than $1.2 billion for the next two-year budget ending in mid-2015.