ALBANY -- The state's ethics board said it will fight a lawsuit this week that seeks to overturn the board's recent regulation to require public-relations firms to register as lobbyists.

The lawsuit against the state Joint Commission on Public Ethics is the latest salvo in a battle over the blurred lines between who is required to register as lobbyists in New York versus who serves as consultants for special interests.

One major point of contention is a requirement that paid consultants and public-relations firms have to publicly disclose their clients and contracts including, in some cases, if they contact the news media.

In a brief statement, JCOPE suggested it expects to prevail in the lawsuit brought by the Center for Competitive Politics, a Washington D.C. based group that's representing five public-relations firms in New York.

"We oppose the motion and look forward to our day in court," the ethics board said.

Public-relations firms received more than $3 million since 2010 from political campaigns and then promoted issues before the Legislature, a review of records last year by Gannett's Albany Bureau as part of its "Power in Money" series found.

Lobbying is big business at the state Capitol: The spending increased 56 percent over the past decade from $144 million in 2005 to $226 million in 2015, the Gannett series found.

In response to the growing influence of the firms, JCOPE in January required the consultants to register as lobbyists and follow state disclosure rules if they reach out to a media outlet "in an attempt to get it to advance the client’s message in an editorial."

David Keating, president of the Center for Competitive Politics, called JCOPE's regulation "absurd, flagrantly unconstitutional, and a new low for one of the worst places in the country to express one's opinion about government."

The public-relations firms who filed the lawsuit are: The November Team, Inc.; Anat Gerstein Inc.; BerlinRosen Public Affairs, Ltd; Risa Heller Communications LLC; and Mercury LLC.

"This case stands at the intersection of a citizen's right to free speech, the press's freedom to report and comment on such speech, and the narrow circumstances in which courts have upheld laws and rules that require the disclosure of lobbying activity," the lawsuit states.

Earlier this week, Assembly Democrats introduced legislation to expand public disclosure of lobbying activities to include non-charitable non-profit organizations, such as 501(c)(3) political groups. The measure, though, would exempt communication with journalists from being disclosed.