BERLIN (Reuters) - Opposition German lawmakers will launch a parliamentary probe into hundreds of millions of euros of contracts awarded by the military to outside consultants, an issue that has sparked a political firestorm in Germany.

Wednesday’s move ratchets up pressure on Defence Minister Ursula von der Leyen, a close ally of Chancellor Angela Merkel who is already under fire for personnel and equipment shortages.

Merkel’s fourth and probably final government has already come close to collapsing twice, and she can ill afford another setback as she tries to lead the coalition forward after giving up the leadership of her party - a sign of her waning authority.

Opposition lawmakers agreed to convene a special committee to investigate possible misconduct over the use of outside consultants after failing to get sufficient answers from the defense ministry.

There was no immediate public comment from the ministry.

The decision follows a scathing internal report by the Federal Audit Office, leaked to the media, that cited dozens of irregularities in hiring outside advisers in contracts worth hundreds of millions of euros in total.

Under German law a special investigative committee can subpoena witness and experts and to order other investigative work by courts and administrative agencies.

Senior members of the opposition Greens, pro-business Free Democrats (FDP) and the hardline Left party announced the move.

“We view it as imperative to carry out our own probe through an investigative committee,” Greens lawmaker Tobias Lindner said in a statement after a six-hour hearing on the issue.

“The violations of rules and inconsistencies in the processes of the Bundeswehr are too egregious to not clear them up,” he said.

The ministry last month told lawmakers it was implementing reforms to prevent further mistakes but said it had not detected any cost to taxpayers from the use of outside experts.

Agnes Strack-Zimmermann, defense spokeswoman for the FDP, said the new investigative body would force former armaments chief Katrin Suder, a former senior executive with McKinsey, and other key players, to testify.