The phrase "are clashing over" is correct and usable in written English.
It can be used to describe a situation where two or more parties are in disagreement or conflict about a particular issue or topic.
Example: "The two companies are clashing over the terms of the merger agreement."
Alternatives: "are in conflict over" or "are disputing over".
The labor organizations and BART's management are clashing over wages and benefits.
Members of an advisory board investigating pollution at Fort Totten are clashing over the board's operations.
Private and federal experts are clashing over how much powdered anthrax Dugway has made.
Even now they are clashing over whether the admission fee should go to the antiquities board or the provincial government.
(Reuters, via The New York Times) Clash of the Carriers Southwest and United are clashing over a proposal from Southwest to expand Houston's Hobby Airport.
Increasingly, with an estimated 17m guns flooding the country, tribes are clashing over access to wells.Yet other security problems are worse.
Moments later, the two were clashing over who said what about whom -- and Minaj was offering Carey a Q-tip to clean out her ears.
Lawyers will soon be clashing over the question in court.
Computer models were clashing over whether the week after next would be wetter because of a significant shift in the jet stream and other major atmospheric conditions, he said.
Behind the scenes, the two regulators have been clashing over a host of issues, officials said, be it the administration's coming regulatory overhaul or Ms. Bair's campaign to shake up the top management at Citigroup.
He channeled public funds to construct schoolrooms and boreholes for wells, lured Western development agencies to his constituency, mediated between ethnic groups in the region that have been clashing over livestock-grazing rights and access to water and distributed some of his ample salary to pay school fees and health-care costs for the indigent.
