BOSTON — The state started a new fiscal year without a formal budget, for the second year in a row, as lawmakers continued to wrangle behind closed doors over a host of thorny issues.

The fiscal year began Monday, but lawmakers haven't reached agreement on controversial policy issues and other sticking points in the nearly $43 billion spending package.

Massachusetts is one of only two states — Ohio is the other — without an approved fiscal 2020 budget, according to the National Conference of State Legislatures.

Instead of facing a potential shutdown, the state government is running on a $5 billion stop-gap budget signed by Lt. Gov. Karyn Polito last week. It is good for one month.

House Speaker Robert DeLeo, D-Winthrop, and Senate President Karen Spilka, D-Ashland, told reporters Monday that the six-member conference committee negotiating a final budget plan worked throughout the weekend but is still wrestling with a host of contentious issues. They declined to discuss what was behind the delay.

"They're working in good faith to come up with solution," DeLeo said. "The issues are more involved than in previous years, and I think that's probably been some of the holdup."

He said it's "very questionable" that a final budget will be approved before Independence Day.

Gov. Charlie Baker tried to put a positive spin on the delay, saying his experience with late budgets means it "usually produces a better product than simply getting there by June 30."

"I don't have a problem with the budget being a week or two late," the Republican chief executive told reporters Monday. "I care a lot more about the quality of the work product."

House Minority Leader Brad Jones, a North Reading Republican, said he doesn't expect a budget to be released before the long holiday weekend.

"It's disappointing that these budget delays seem to becoming the rule, not the exception," Jones said Monday. "It happens more than it should."

Lawmakers hope to avoid the embarrassment of the last budget cycle when Massachusetts was last in the nation to approve a spending plan for the 2019 fiscal year.

Like most states, Massachusetts is required to have a budget  — even if temporary — to keep the government running, but there are no penalties for approving it late.

Exactly what's holding up the budget isn't clear as the six-member committee of lawmakers negotiating a final spending package has closed its proceedings to the press and public.

One contentious issue is Baker's proposal to rein in the growth of prescription drug spending by MassHealth, which serves 1.9 million low- and moderate-income people.

Baker wants to allow the state to publicly post the "value" of a drug if it is found to be unreasonably priced and if there is no agreement on supplemental rebates with the manufacturer.

His plan would require drug companies to participate in public hearings and report pricing information to state agencies. Those that don't cooperate could be sued by the attorney general's office.

Both the House and Senate added parts of Baker's MassHealth plan to their budgets, but the House left out some of the tougher provisions, including referrals to the attorney general.

Another controversial idea is Baker’s plan to tax opioid manufacturers to help pay for substance abuse treatment. He wants a 15% tax on the overall sales of opioid makers, such as Purdue Pharma. The tax, expected to raise $14 million a year, would help pay for more beds in treatment centers, recovery and prevention programs.

The Senate voted to include Baker's proposal in its version of the budget, but the House didn't. Supporters of the idea say it will punish an industry that many blame for a wave of addiction, while raising money for treatment and prevention.

There are also differences on school funding, nursing home aid and a tuition freeze at the University of Massachusetts on which lawmakers must reach consensus.

Once lawmakers agree on a final spending plan, the House and Senate will take up or down votes, with no amendments allowed. The bill then goes to Baker, who has 10 days to review it.

Democrats have large enough majorities in both chambers to override any of Baker's vetoes on policy or spending items, as they have in several previous budget cycles.

House and Senate leaders have told lawmakers to be on call for a possible budget session Tuesday or Wednesday in case the committee reaches a deal on the final spending plan.

Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites.