BERLIN (Reuters) - Germany risks losing international credibility if it retreats from its commitment to increase military spending towards the NATO target, a key member of Chancellor Angela Merkel’s conservatives said on Wednesday.

FILE PHOTO - German Foreign Minister Sigmar Gabriel talks at the Munich Security Conference in Munich, Germany, February 17, 2018. REUTERS/Ralph Orlowski

Norbert Roettgen blasted Foreign Minister Sigmar Gabriel, a Social Democrat, for questioning the target of 2 percent of GDP “shortly after the ink had dried” on a deal by their two blocs to renew the “grand coalition” that has ruled since 2013.

SPD members, who must sign off on the deal, began voting in a mail ballot that runs through March 2. A vote against the deal would likely result in a minority government or a new election.

The coalition agreement underscores Germany’s intention to meet its commitments to NATO, but does not explicitly mention the goal of 2 percent spending by 2024.

Roettgen, conservative head of the foreign affairs committee in parliament, told Reuters in an interview that Germany could and should increase military spending to around 1.4 percent or 1.5 percent of economic output by the end of the next four-year legislative period, up from around 1.2 percent now.

“It is doable and it would ensure our credibility, and it would be a step toward ensuring that Germany is seen as a country that ... can also wield political influence,” he said.

U.S. President Donald Trump and other NATO allies are pressing Germany as Europe’s biggest economy and a key power in NATO to spend more on its military, which came under fire this week for nagging shortfalls in equipment.

The German defense ministry on Wednesday said its efforts to improve the readiness of key weapons were starting to pay off.

It said 57 percent of its 5,000 major weapons - aircraft, ships and ground vehicles - were available for use at the end of 2017, up from 46 percent in March 2015.

But officials have said it will take 10 years to reverse erosion caused by years of declining military spending.

SPD RESISTANCE

Gabriel repeated his scepticism about the NATO target at the Munich Security Conference last week, while senior leaders from France, Poland and Estonia had demanded that all NATO members including Germany should stick to the agreed targets.

“He’s damaging the credibility of Germany,” Roettgen said. “If we do not reliably stand by commitments we made to NATO, we will lose standing and influence in Washington, and even Moscow won’t take us seriously.”

The controversy highlighted continuing frictions between the two German political blocs on foreign policy issues, security and future ties with Russia that are likely to continue even if SPD members vote to approve the tie-up, Roettgen said.

The coalition partners agreed to add about 1 billion euros to the previously planned budget for the military, which foresees modest gains, although economic growth could offset any increases in the percentage of GDP spent.

The parties also agreed in the coalition agreement to prioritize foreign, security and development spending if additional funds became available due to increased tax revenues.

Roettgen said he believed that some U.S. government officials understood the dangers of scrapping a 2015 accord under which Iran agreed to restrict its nuclear program in exchange for relief from crippling economic sanctions.

Trump is critical of the deal and had demanded it be revised if Washington is to stay in the deal. European countries, which adamantly oppose any dismantling of the deal, are in intensive discussions with Washington on the issue, Roettgen said.

“People close to the president understand that cancelling the agreement would have a devastating impact on the reputation of the United States as a reliable partner, and the relationship with Europe,” he said. “That is why they will look for ways to avoid this conflict.”

A State Department cable first reported this week by Reuters sketched out a path under which Germany, France and Britain would commit to try to improve the deal over time in return for Trump keeping the pact alive by renewing U.S. sanctions relief in May.