One of New Jersey's top property tax relief programs for hundreds of thousands of senior, disabled and low-income homeowners is underfunded by about $150 million in the state budget proposal that Gov. Phil Murphy unveiled earlier this week.

The new governor, a Democrat, budgeted just $143.5 million for the Homestead credit program, for which full funding is closer to $290 million.

Murphy's administration wouldn't say whether full credits would be paid out to homeowners this year, though a top Democratic lawmaker says the state Legislature will ensure they are.

"I have to believe that this was an honest oversight. But, the Legislature will act to ensure that the missing funds for the program are put back into the budget," state Sen. Paul Sarlo, D-Bergen. "We understand that this is a new administration that is new to the practices of governing and the work needed to enact an effective budget."

It was the Legislature, however, that first reduced funding for the program in the current year's budget, an accounting trick borrowed from the Christie administration.

Faced with a $527 million budget shortfall last spring, Gov. Chris Christie, a Republican, floated the possibility of pushing the $300 million Homestead credit bill from one fiscal year, the 2017 fiscal year, into the next, 2018, but backed off because it conflicted with accounting rules.

But in the messy budget negotiations that followed -- and ultimately led to a government shutdown, the Legislature slashed the payment for this fiscal year, 2018, from $291.9 million to $147.3 million (It's since been boosted to $156 million).

Lawmakers expected the state, under a new governor, to pony up the rest of the money in the next fiscal year. But now that bill comes due, and Murphy's budget for the fiscal year that begins July 1 doesn't include enough cash to pay the full credit in 2018 and 2019.

A spokeswoman for the state Treasury Department, Jennifer Sciortino, said Murphy wasn't the one who sliced funding for the program.

"The $156 million included in this year's budget is the appropriation that was approved by the Legislature in June 2017 and property taxpayers should start receiving that benefit around May 1," she said.

"The governor's proposed budget for FY '19 proposes a continuation of that program unaltered with a slight change to reflect forecasted costs (i.e. program cost savings)."

The benefit is open to senior and disabled homeowners earning less than $150,000 and all other homeowners with income below $75,000.

When fully funded a few years ago, the benefit averaged $515 for seniors and disabled homeowners and $401 for all other eligible homeowners. It was about half that when the program was half-funded.

It's unclear how these accounting maneuvers will trickle down to taxpayers because of the mismatch between the state's June to July fiscal year and the calendar year for property taxes.

Christie's administration played shell games with the funding for the program, delaying payments to help manage budget shortfalls. Homeowners waited 11 months for their 2011 benefit and 17 months for their 2012 benefits, which they received in May 2015.

Gov. Brendan Byrne instituted the first iteration of the Homestead rebate in 1977. During the Great Recession and under Gov. Jon Corzine, higher-earning households were cut out, reducing the number of property owners eligible and the program's outlay.

Funding for the program continues to decline, the result of tight eligibility requirements and a shrinking pool of participants. The state paid out more than $1.8 billion in fiscal year 2008, $1.5 billion in 2009, $1 billion in 2010, $266 million in 2011 and $408 million in 2012.

While underfunding the Homestead benefit, Murphy's first budget raises the state's gross income tax deduction for property tax payments from $10,000 to $15,000. This follows federal tax reform that limited the deduction for state and local taxes to $10,000.

New Jersey's average tax bill was $8,690 last year.

Samantha Marcus may be reached at smarcus@njadvancemedia.com . Follow her on Twitter @samanthamarcus.