Nassau property owners are expected to receive their general tax bills late because of last-minute changes by the county to its assessment roll.

Hempstead Town has filed suit against Nassau over the issue, which involves adjusting the values of hundreds of properties owned by the Long Island Power Authority and operated by PSEG-Long Island. The town’s request for a temporary injunction to stop the assessment roll changes was to be heard in State Supreme Court Wednesday.

State law says property taxes for Nassau County, towns and special taxing districts are due Jan. 1, but property owners can pay the first half by Feb. 10 without penalty.

Town tax receivers generally mail the tax bills the first week in January but officials acknowledged Tuesday that the bills will be delayed because the county’s late transmission of assessment and tax rate information.

The towns said they received the raw data Tuesday afternoon.

The delays came after the county assessor removed more than 600 LIPA properties from Nassau’s overall assessment roll and capped any increase in the utility’s tax payments at 2 percent. LIPA had argued that state law requires its properties to be removed from the tax roll, with the utility instead making “payments in lieu of taxes,” or pilots.

advertisement | advertise on newsday

The assessor’s office told county lawmakers it finished calculating the LIPA changes at 3 p.m. Dec. 20. The county legislature approved the amended assessment roll the next day. Legis. Delia DeRiggi-Whitton (D-Glen Cove) abstained, saying she was not satisfied with answers to her questions.

DeRiggi-Whitton said this week that she worried that the legislature had voted “on something that wasn’t complete ... Taxes are a major concern for our constituents. Proper time and skill should be exercised before adjusting the tax levy.”

But County officials said the rolls had been completed, but needed to be rechecked. They also noted the tax data has gone out late in the past without forcing unduly late tax bills.

But Town of Hempstead officials worry that residents will have little time to pay without penalty. Spokesman Michael Deery said, “The town just wants to make sure that taxpayers receive their tax bills on time.”

Oyster Bay Town Tax Receiver James Stefanich said if he could verify the data he could have tax amounts posted on the town website in about a week and bills mailed by mid-January. But glitches could force further delays. he said.

In its lawsuit, Hempstead contends Nassau changed the assessment roll and removed 250 LIPA properties located within the town without notice after Hempstead adopted its budget and tax levy. The town, represented by the outside law firm of Berkman, Henock, Peterson, Peddy & Fenchel, notes the LIPA parcels had been on the assessment roll for nearly 35 years. Removing the utility properties — without pilots in place — alters the town tax rates when Hempstead no longer can change its budget.

“This last minute conduct, which violates the town law, ... wreaks havoc on the town’s budgetary process and is both inexplicable and inexcusable,” the lawsuit states.

County attorney Carnell Foskey declined to comment on the lawsuit but said, “The tax levy for 2016 is consistent with state and local law and it provides for collection of taxes that is fair to all the taxpayers.”

A spokesman for LIPA said it does not comment on litigation.