The state Legislature’s budget experts delivered a couple of tough warnings for Gov. Phil Murphy’s administration and New Jersey motorists on Monday.

New Jersey’s tax collections could register $292 million below Murphy’s state budget forecasts through June 2020.

And New Jersey’s gas tax could rise for the third time since 2016 unless consumption rises in the next few months.

Those were the early budget assessments the nonpartisan state Office of Legislative Service delivered to state lawmakers Monday morning.

New Jersey’s treasurer, however, later said she is “cautiously optimistic” the Murphy administration will not have to enact another gas tax increase, and that no rate increase is “assumed in the current projection.”

OLS’s budget experts told the state Assembly Budget Committee on Monday that it projects tax collections are trailing the governor’s estimates by $109.2 million this year and $182.8 million next fiscal year.

Given the size of Murphy’s $38.6 billion proposed budget, the office’s estimates are remarkably close for both this fiscal year and next. But the Office of Legislative Services is slightly less optimistic than the treasurer about the flow of taxes into state coffers.

Treasurer Elizabeth Muoio addressed the committee Monday afternoon.

OLS’s analysts stressed the extreme importance of April tax collections. Both are counting on an influx of final estimated tax returns to make up for a winter slump they attributed to taxpayers reacting to federal tax changes.

“Under this theory, a large part of this December’s shortfall will be made up in April final payments — making the April surprise this year more important than a typical year,” OLS analyst David Drescher told the committee.

In addition to big tax changes at the federal level, budget analysts are also grappling with increases to the gross income and corporate business taxes adopted last year.

“A variety of policy changes and other factors have come together to make fiscal years 2019 and 2020 some of the most difficult to forecast in decades," Drescher said.

OLS and the treasurer disagree slightly on how revenues will perform through the rest of the fiscal year, which ends in June. OLS’s income tax projection is $31 million less than the Murphy administration, its sales tax projection is $123 million lower, and its insurance premium tax estimate is $56 million lower.

“The Gross Income Tax is New Jersey’s largest single revenue source, and as of today it looks to be our most problematic. Collections to date are far short of the same period last fiscal year,” Drescher said.

But the legislative office is expecting corporation business taxes to come in $77 million higher than the treasurer, helping the state dodge a bigger potential shortfall if OLS’s estimates prove accurate.

Drescher also warned drivers in New Jersey could be in store for another gas tax increase this fall without a big surge in gasoline consumption in coming months.

State law requires that the treasurer increase the tax rate each year to ensure it brings in enough cash to pay the bills for road and rail projects around the state.

The tax rose 4.3 cents per gallon last fall, just two years after motorists were stung with a 23-cent-per gallon increase signed by then-Gov. Chris Christie to raise money for road and rail projects across the Garden State.

Muoio later told the committee she’s not anticipating higher gas taxes right now.

“While consumption is likely to decline somewhat further, with the 4.3 cent rate increase in effect for an entire 12-month cycle, we are cautiously optimistic that total revenues will remain stable," she said. "As I said earlier, this will be revisited in August as required by law, but no rate change is assumed in the current projection.”

That increase brought the total state taxes to 41.4 cents on each gallon of motor fuels pumped in New Jersey, and 48.4 cents on each gallon of diesel.

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