Bloody fighting between Myanmar's army and a separatist movement is proving an "insurmountable barrier" to the return of the country's displaced Rohingya minority, a UN official warned Tuesday.

The mostly Muslim Rohingya have been persecuted in Myanmar for decades, with many escaping the 2017 military clampdown labeled a "genocide" by some countries and now finding themselves unable to return as fighting rages in Rakhine state.

Rakhine State, their homeland in western Myanmar, has been the site of some of the most intense fighting in the conflict tearing the country apart since the 2021 military coup that overthrew the democratic government.

"As to the Rohingya, forcibly displaced again from Myanmar more than eight years ago, the escalating conflict in the country presents a seemingly insurmountable barrier to their return," the UN's Special Envoy on Myanmar Julie Bishop said in a speech.

"They wish to return home, to Rakhine, to rebuild their lives, and become leaders of their communities with control over their destiny."

The human rights and humanitarian situation in Myanmar's Rakhine State has sharply deteriorated since November 2023, deepening the life-threatening conditions faced by the Rohingya living there.

The impoverished state -- a riverine slice of coastal Myanmar bordering Bangladesh -- has witnessed intense suffering in Myanmar's civil war, triggered by a 2021 coup deposing the democratic government.

Both the military and local ethnic fighters from the Arakan Army "have committed and continue to commit serious atrocity crimes against the Rohingya with impunity -- in flagrant violation of international law," the UN human rights office said previously.