The flotilla, organized by a coalition of aid groups, has yet to receive permission to enter Myanmar, sparking fears of a confrontation with security forces that could worsen Myanmar's already-frayed ties with predominantly Muslim Malaysia, Reuters reported.
Malaysia has been an outspoken critic of the Myanmar government's handling of a violent crackdown in Rakhine, which has killed scores of people and displaced 30,0000 Rohingya, amid allegations of abuses by security forces.
The Malaysian Consultative Council of Islamic Organizations secretary-general Zulhanis Zainol said the flotilla's organizers had applied for permission to enter Myanmar through its embassy in Kuala Lumpur, but had yet to receive a reply.
"Even if we do not receive a response, we will continue to sail as we believe this is an important humanitarian mission," he said.
Myanmar's presidential office denied it had received a request and said it would not accept the flotilla's arrival without prior permission.
"If they are looking for trouble, we will not accept that," Zaw Htay, spokesman for the presidential office said.
"No non-Myanmar citizens can enter our body of water without our permission. If they do, we will respond – we will not attack them, but we will not receive them."
The flotilla, departing from Malaysia on Jan. 10, would be carrying 1,000 tons of rice, medical aid and other essentials for the Rohingya population.
Earlier this month, Malaysia urged the Association of South East Asian Nations (ASEAN) to coordinate humanitarian aid and investigate alleged atrocities committed against Rohingya Muslims.
Both Malaysia and Myanmar are members of the 10-nation grouping, which has a long-standing policy of not getting involved in each other's internal affairs.
An estimated 150,000 to 200,000 Rohingyas, displaced by previous violence, live in Malaysia.
Myanmar has previously said access to Rakhine for humanitarian assistance would be open, but certain Rohingya communities have remained off-limits to aid agencies on security grounds.