The conflict between Gov. Phil Murphy and fellow Democrats who control the New Jersey Legislature hit a new high Thursday.

Both of the state's top legislative leaders warned the new governor not to let an outside group put pressure on lawmakers to get behind his state budget proposal as the clock to the June 30 deadline counts down.

The men reacted to a report that Murphy's allies might launch a public campaign to pitch his budget, which includes tax increases that top lawmakers have not supported. The campaign could include digital and TV ads.

"Trying to pressure our members would be an unfortunate decision," state Assembly Speaker Craig Coughlin, D-Middlesex, said in a statement.

"Our caucus is focused on crafting a budget that represents the best interests of the taxpayers and no amount of pressure will deter us from doing what we believe to be in the best interest of New Jersey's families," Coughlin said. "I would strongly advise the administration to distance itself from these remarks and these tactics."

State Senate President Stephen Sweeney said he's ready if Murphy's allies run ads.

"If they want to run a campaign to attack legislators, bring it on," Sweeney, D-Gloucester, told NJ Advance Media. "We will continue to work for working-class families in this state."

The outside group that roiled lawmakers is called New Direction New Jersey, formed by a series of former Murphy campaign consultants and staffers, including Brendan Gill, Murphy's former campaign manager.

Gill said group planned to begin digital and possible TV ads in the coming weeks, according to a report in The Record.

When asked by NJ Advance Media, Gill declined to discuss any specifics on future ad campaigns. Instead, he said in a statement that the group doesn't have any plans to "pressure" lawmakers.

"New Direction New Jersey is focused on a positive mission of building a stronger and fairer New Jersey. Any indication of exerting negative pressure on legislators was a mischaracterization on my part," Gill said.

A spokesman for Murphy, Dan Bryan, declined to comment.

State Assembly Speaker Craig Coughlin (let) smiles with state Senate President Stephen Sweeney (right) at the Statehouse in Trenton earlier this year.

Murphy has called for more than $1.5 billion in new taxes in his first budget to help pay for increases to education, transportation, public-worker pensions, and more.

During a speech Thursday, he pitched the increases as "the right thing to do" to help strengthen New Jersey's economy and boost the middle class.

But with Democratic lawmakers still opposed, that means the stage is set for gridlock when it comes time to pass a budget by the end of June.

If a budget isn't passed and signed by the governor at that point, the state government shuts down.

Sweeney said he still believes tax hikes should be a last resort. He said Murphy "hasn't even attempted" to try to curtail spending instead.

"Finding more revenue is not the answer," Sweeney said. "The answer is dealing with cost."

For Coughlin, the statement was his most forceful condemnation of the governor to date.

The speaker has publicly positioned himself as the quiet observer as Murphy and Sweeney have taken shots at one another.

Both men of publicly denied a rift between one another. But the privately discussed chill spilled out into recently when Sweeney said Murphy "sounded like Donald Trump" after a spat over the governor's picks to oversee education departments.

NJ Advance Media staff writer Brent Johnson contributed to this report.

Matt Arco may be reached at marco@njadvancemedia.com. Follow him on Twitter @MatthewArco or Facebook.