BERLIN (AP) — Germany's government is facing a major test after two junior partners in Chancellor Olaf Scholz's three-party coalition sparred publicly over a key element in the country's ambitious climate policy.

Economy and Energy Minister Robert Habeck of the environmentalist Greens accused the libertarian Free Democratic Party of backtracking on agreements by refusing to let lawmakers debate a bill for replacing home heating systems with greener alternatives.

The bill was approved by Cabinet in March after months of intense haggling between the parties. A major stumbling block was the Green party's demand that the installation of new oil or gas furnaces should be banned from next year to ensure Germany can meet its target of reducing greenhouse gas emissions to net zero by 2045.

A compromise saw numerous exceptions and subsidies included in the bill, but the Free Democrats later said they still had misgivings, meaning it is unlikely to be taken up by parliament before the summer recess.

“In my view this is a breach of promise,” Habeck told reporters in Berlin.

“If you enter into government and give your word, then you stand by your word,” he added.

Populist newspapers have claimed that installing climate-friendly heat pumps will be hugely expensive and may not be feasible in older buildings, though such systems are widely used in neighboring countries. Experts counter that a failure to replace fossil fuel heatings will end up costing homeowners more as the price of oil and gas rise sharply in the coming decades because of emissions surcharges agreed at the European level.

Scholz has largely tried to sit out the spat between his two junior partners, but told members of his own center-left Social Democratic Party on Tuesday that Germany's transformation to a carbon-neutral economy can only succeed if politicians can convince voters that their fears are taken seriously and the changes will benefit them.