The Democrats who lead the state House and Senate are at odds on some closely watched policy items in the frenzied final stretch of major lawmaking for the year, but they found an unusual piece of common ground this week: using the same set of words to swipe at each other.

As the July 31 deadline for passing controversial bills nears, the comments from House Speaker Ron Mariano and Senate President Karen Spilka raise questions about the future of both a Senate-backed bid to bring overdose prevention centers to Massachusetts and a property tax plan from Boston Mayor Michelle Wu.

On Monday, Senate Democrats put forward their own version of a House-passed bill aimed at staving off opioid overdoses. The new Senate bill includes a measure that House lawmakers left out of their bill – language that would authorize cities and towns to open overdose prevention centers, sites where people can use illicit drugs under medical supervision.

A frustrated Mariano balked Monday afternoon at the controversial proposal newly emerging from the Senate so close to Wednesday’s deadline.

“Anytime you release a bill the day before the session ends, it’s a very difficult expectation for us to hear it, especially when it has proposals, major proposals, that we haven’t even had the opportunity to debate or vote on,” he told reporters. “It sort of tells me you’re not really serious about passing the bill to begin with, so that’s sort of where we’re at.”

A day later, with both legislative branches in session to vote on late-moving bills, Spilka was prepared with a rebuttal. She read a nearly identical comment off a sheet of paper when a reporter asked her how the Senate feels about Boston Mayor Michelle Wu’s plan to shift more of the city’s property tax burden onto commercial real estate as a way to shield homeowners from a big hike in their bills.

The House voted 132-24 to pass the Boston property tax home rule petition Tuesday, after Wu said she’d issue an executive order limiting the scope of the tax changes if the bill becomes law.

The language the House approved is the same as when a joint House-Senate committee advanced it earlier this month, but Spilka said she couldn’t comment in detail since senators had yet to debate on or see the new deal with City Hall.

“And as you know, any time you release a bill the day before session ends, it’s a very difficult expectation for us to hear it, especially when it has new proposals and major proposals that haven’t had the opportunity to be debated or voted on,” Spilka said. “It sort of tells you that they’re not really serious about passing the bill to begin with.”

Mariano, a Quincy Democrat, said Tuesday he sees a “major difference” between his chamber approving the Boston tax bill, which was green-lit by the city council and not subject to changes from the Legislature, and the Senate’s move on overdose prevention centers.

Any tension between the House and Senate has the potential to derail the effort to find compromise on a host of key policies still unresolved in the last hours of negotiating time. At least eight separate teams of Senate and House lawmakers were still working late Tuesday afternoon to reach deals on final bills dealing with housing policy, clean energy, veterans benefits, prescription drug costs, hospital oversight and more.

Mariano acknowledged there was a danger of frustration between the two chambers bubbling over to complicate talks on other major priorities.

“But the frustration is real,” he said.

Spilka, for her part, said the Senate “will continue to roll up its sleeves and work to produce good substantive policy for the people of the Commonwealth until the last day, the last minute of the session.”

Ironically, Tuesday’s remarks from Spilka and Mariano came as they left a bill signing ceremony where House and Senate leaders each heralded the collaboration it took to usher a new gun reform law over the finish line.

“Today we celebrate what we can achieve when we come together, work together and talk to each other,” Spilka, an Ashland Democrat, said during the ceremony. “There is no issue that we cannot solve, no matter how detailed and no matter how complex.”