The ceasefire announced on Saturday in a statement by the Arakan Rohingya Salvation Army (ARSA) started on Sunday.
"ARSA strongly encourages all concerned humanitarian actors resume their humanitarian assistance to all victims of the humanitarian crisis, irrespective of ethnic or religious background during the ceasefire period," the group said.
The statement also called on Myanmar's military to also temporarily lay down arms.
Nearly 300,000 Rohingya have fled from Rakhine to neighboring Bangladesh and 30,000 non-Muslim civilians have been displaced inside Myanmar after the military launched a counter-offensive following attacks by ARSA on 30 police posts and an army base last month.
Witnesses say entire Rohingya villages have been burned to the ground since the security forces' operation, while the UN Secretary-General Antonio Guterres has warned of the risk of ethnic cleansing, appealing to the country's authorities to end violence against Rohingya Muslims in Rakhine state.
Calls for safe access
The impact of ARSA's ceasefire declaration is unclear. The group does not appear to have been able to put up significant resistance against the military force unleashed in Rakhine.
Al Jazeera's Florence Looi, reporting from the city of Yangon in Myanmar, said the army had not responded yet, but it would be hard for them to reject the ceasefire.
"It will be more difficult for the Myanmar military to say it is carrying out an operation that many rights groups have said looks more and more like a campaign of ethnic cleansing, and of disproportionate targeting of Rohingya civilians instead of Rohingya fighters," she said.
Joy Singhal, of the International Federation of Red Cross and Red Crescent Societies (IFRC), told Al Jazeera from Yangon that the ceasefire from both sides was essential for the work the group intends to carry out in Rakhine.
"We are asking for a safe access to be able to meet a large amount of humanitarian needs, including emergency food supplies, safe drinking water, transportation for the families to a safer area," he said.
IFRC is scaling up its operations in Rakhine after the United Nations had to suspend activities there following government suggestions that its agency had supported the rebels.
Myanmar's government had invited IFRC to assist them, according to Singhal.
The authorities will coordinate and facilitate the distribution of aid, so some of the Rohingya fear they will be neglected.