Communal bloodshed in western Myanmar risks developing into "armed terrorist acts", the government said Wednesday, after security forces were targeted by homemade firearms in deadly fighting.

Myanmar said 180 guns were seized during the new wave of clashes between Buddhists and Muslims in Rakhine state, which has killed dozens, displaced tens of thousands and seen whole neighbourhoods razed.

It said several people had been arrested on suspicion of making the weapons.

"The clashes between two communities are likely to turn from normal unrest to armed terrorist acts after the security forces were attacked with handmade guns," the government said, in a statement on the president's website.

Decades-old animosity between Buddhists and minority Rohingya Muslims exploded in June after the apparent rape and murder of an ethnic Rakhine woman sparked a series of revenge attacks.

The latest clashes have caused more than 32,000 people to flee their homes this month, the government said, adding to the 75,000 people already crammed into overcrowded camps after the earlier fighting.

Myanmar said both local and international organisations were "involved" in the conflict, without elaborating on their identities or exact role.

"In order not to face continuous incidents that harm the lives and stability of the people, the government will take serious action against those who incited the people to fight," it said.

The toll from the clashes, which began on October 21, stands at 89 people killed, with 136 injured and more than 5,000 homes reduced to ash in a wave of arson.

Many of the casualties suffered gunshot wounds and authorities have admitted to shooting into crowds of rioters as the fighting intensified.

Authorities have struggled to end the violence, which flared again on Tuesday in renewed clashes that saw police shoot and kill one ethnic Rakhine, according to a government official who declined to be named.

Myanmar's 800,000 stateless Rohingya, viewed by the United Nations as among the most persecuted minorities on the planet, are seen by the government and many Burmese as illegal immigrants from neighbouring Bangladesh.

They face discrimination that activists say has led to a deepening alienation from Buddhists.

But other Muslim communities in Rakhine have also been swept up in the latest violence, including the Kaman, one of Myanmar's officially recognised ethnic groups.

The United Nations refugee agency on Tuesday said food, water and medical help are in short supply at camps in western Myanmar that are "stretched beyond capacity".

It raised concerns about getting aid to an unknown number of displaced people in remote areas.

The unrest sparked an exodus of thousands, with many travelling in boats towards the state capital Sittwe in hopes of finding shelter at the camps on the coast near the outskirts of the city.

Bangladesh police and a Rohingya advocacy group on Wednesday said about 130 people were missing after a boat carrying Rohingya refugees who were headed for Malaysia sank off Bangladesh.

Since the unrest erupted in June, Bangladesh has turned away boatloads of fleeing Rohingya, drawing criticism from the United Nations.

Myanmar has rejected an offer by the Association of Southeast Asian Nations to open talks aimed at quelling the conflict, the bloc's Secretary-General Surin Pitsuwan told reporters in Malaysia on Tuesday.

He had earlier warned that the bloodshed could "radicalise" the Rohingya and destabilise the "entire region", according to reports.