Ethiopia’s Nobel Peace Prize-winning prime minister has said he will lead his country’s army "from the battlefront” beginning on Tuesday, a dramatic new step as the year-long conflict moves closer to the capital Addis Ababa.

"Starting tomorrow, I will mobilise to the front to lead the defence forces,” Abiy Ahmed said in a statement posted on Twitter late on Monday.

"Those who want to be among the Ethiopian children who will be hailed by history, rise up for your country today. Let’s meet at the battlefront.”

Tens of thousands of people are estimated to have been killed in the war between Ethiopian and allied forces, and fighters from the country’s northern Tigray region, who dominated the national government before Abiy took office. The United States and others have warned that Africa’s second-most populous country could fracture and destabilise the rest of the region.

The statement by the 45-year-old prime minister, a former soldier, did not say where exactly he will go Tuesday. His spokeswoman, Billene Seyoum, did not respond to a request for comment from the Associated Press news agency.

Former US diplomat William Lawrence noted Abiy had used a lot of war imagery when accepting his Nobel prize but that had been to highlight the horror of war.

"And here we are almost full circle with a Nobel Peace Prize winner using the most bellicose language to try and ramp up the stakes ahead of the defence of not only Ethiopia, but life and death,” Lawrence said. "He says he’s basically willing to die for the cause.”

Abiy’s comments came as the Tigray People’s Liberation Front (TPLF) rebel group continued to press towards Addis Ababa, claiming control of the town of Shewa Robit, just 220 kilometres (136 miles) northeast of the capital by road.

It also followed a meeting of the ruling Prosperity Party’s executive committee to discuss the war.

Defence Minister Abraham Belay told state-affiliated media after the meeting that security forces would embark on a "different action” without providing details.

"We can’t continue like this, that means there will be change,” Belay said.

"What happened and is happening to our people, the abuses being meted out by this destructive, terrorist, robber group, can’t continue.”