ALBANY – A pair of minority-party lawmakers are threatening to file a constitutional lawsuit unless Governor Pataki and legislative leaders reform the notoriously dysfunctional way state government does business.

The proposed suit by Senator Liz Krueger, a Democrat of Manhattan, and Assemblyman Thomas Kirwan, a Republican of Newburgh, would claim the existing rules and procedures – which concentrate power in the hands of the Senate majority leader and the Assembly speaker – “discriminate” against lawmakers in the minority parties, in violation of the federal and state constitutions.

If Senate Republicans and Assembly Democrats don’t change those rules sufficiently early next year, the two lawmakers are preparing to go to court as early as January 18, according to a summary of their plans that was distributed to reporters Wednesday.

Ms. Krueger, Mr. Kirwan, and their attorneys are to discuss the lawsuit in detail in a news conference Monday at the Capitol.

The threat of court action could add to the pressure on the Senate majority leader, Joseph Bruno, the Assembly speaker, Sheldon Silver, and Mr. Pataki to loosen their tight grip on the reins of state government. One major element of the reform drive is a resolution to change Assembly rules. That proposal, by Scott Stringer, a Democrat of Manhattan, would, among other things, make it easier to bring legislation to the Assembly floor, require members to be in the chamber to vote, and give each member a minimum allowance for staff and office expenses, rather than leaving that to the speaker’s discretion.

Although Messrs. Bruno and Silver have pledged to consider rules changes like those over the next month, Ms. Krueger said she doubts Senate Republicans will cede much of their power voluntarily. The threat of a legal action, she said, provides “one more reason to hope that both houses of the Legislature and the governor will want to do the right thing in January and avoid the necessity of having to go into the court system.”

Ms. Krueger and Mr. Kirwan declined to elaborate on the goals of their suit or its legal arguments, saying they preferred to wait until Monday’s event.

“The draft complaint identifies numerous rules and practices of the Legislature and Governor that illegally discriminate against legislators belonging to the minority party of each house in violation of the United States Constitution, the New York State Constitution, and the laws of New York,” the summary given to reporters said. “These rules and practices illegitimately centralize power in the hands of the ‘three men,’ and prevent minority party legislators in particular from adequately representing their constituents.”

The two legislators’ attorneys are the director of the Urban Justice Center, Douglas Lasdon; a former counsel to Governor Cuomo and former president of the Association of the Bar of the City of New York, Evan Davis, and Mr. Davis’s firm, Cleary Gottlieb Steen & Hamilton, of Manhattan. All are donating their services.

By tradition and design, the governor and top legislative leaders make most of the important decisions in secretive negotiations among themselves, a process known derisively as “three men in a room.”

In the Legislature, the majority parties use their power not only to deflect minority-sponsored bills, but to prevent most such measures from even coming to a vote. Senate Republicans and Assembly Democrats also direct the lion’s share of discretionary money from the state budget to their members’ districts, award their members larger budgets for staff and supplies, and draw the boundaries of legislative districts to maximize their respective parties’ advantage in elections.

Those long-standing practices have come under increasing criticism in recent years, as experts have linked them to chronic gridlock at the Capitol, including a 20-year streak of late budgets. This summer, a report from the Brennan Center for Justice at New York University identified New York’s state government as the most dysfunctional in the country.

Members of the minority parties have long complained about their treatment, but have never taken their grievances to court. The lawsuit also violates an Albany taboo against cooperation between the chambers’ minority parties.

Ms. Krueger noted that watchdog groups across the political spectrum have deplored Albany’s way of doing business as inefficient and undemocratic.

“This is not one of those issues that is ‘D’ or ‘R,’ left or right,” Ms. Krueger said. “If you follow Albany at all, no matter where you come from ideologically, you say to yourself, ‘This isn’t working.'”

Mr. Kirwan described himself and Ms. Krueger as “a political odd couple.”

“I’m a right-wing lunatic,” the Republican said, “and Liz could charitably be described as to the left of center.”