Al Qaeda's intervention in the humanitarian crisis in Myanmar has stoked new fears that Rohingya militants have the backing of global jihadist groups, including Islamic State (IS).

Al Qaeda has issued a statement urging Muslims around the world to send aid, weapons and military support to Rohingya Muslims in the majority Buddhist Rakhine state.

Nearly 400,000 Rohingyas have fled to Bangladesh since late August after a brutal military crackdown by Myanmar's military in retaliation for attacks by Rohingya militants on several police posts and an army base.

Al Qaeda has warned Myanmar will face punishment for its "crimes against the Rohingyas".

"The savage treatment meted out to our Muslim brothers … shall not pass without punishment," Al Qaeda said in a statement, according to the SITE monitoring group.

"The Government of Myanmar shall be made to taste what our Muslim brothers have tasted."

Sorry, this video has expired Explainer: Who are the Rohingya and what is happening in Myanmar?

The United Nations has condemned Myanmar's crackdown on Rohingyas as a "textbook" case of ethnic cleansing.

But Myanmar said it is dealing with a terrorist group, namely the Arakan Rohingya Salvation Army (ARSA), which has previously been linked to extremist groups including IS.

Reports of links between Rohingya militants and jihadist groups

A former Australian ambassador to Myanmar, Trevor Wilson, said ARSA shows many of the attributes of Islamist terrorist groups elsewhere.

"ARSA has declared links with Islamic State, uses crude anti-authoritarian propaganda, and shows a willingness to introduce arms into what was previously an 'unarmed political struggle'," he wrote in an online post for the Asian Studies Association.

"The utterly opportunistic nature of their public profile, and blatant use of ordinary Rohingya to cover for their own extremism are similarly shared attributes."

Mr Wilson said ARSA's destabilising influence in Myanmar has attracted attention from intelligence agencies, and referred specifically to a report on a news site run by exiled Burmese journalists — Mizzima — that said IS and Pakistan were behind the Rohingya attacks on Myanmar security forces.

It said the Rohingya leader behind the attacks, Hafiz Tohar, had spoken at length with extremists in Pakistan and Iraq in the two days before last month's attacks on Myanmar security posts.

"Indian and Bangladesh intelligence officials say that they have intercepted three long-duration calls between Hafiz Tohar … that hold the key to why the militant group unleashed the pre-dawn offensive against Myanmar security forces," the report said.

The report quoted an unnamed Bangladeshi intelligence officer who said the attacks on Myanmar forces aimed to cause trouble for Aung San Suu Kyi's Government in Myanmar and bolster the Rohingya insurgency in Rakhine state.

Tohar is believed to have trained with the Pakistani Taliban, and is widely blamed for similar attacks in Myanmar last October.

Myanmar's military launched a brutal crackdown on the Rohingyas. ( AP: Bernat Armangue, File )

Expert warns of Rohingyas obtaining weapons

The Mizzima report is difficult to verify. But other reports bolster evidence of a link between jihadist groups and militant extremism in Myanmar.

In a separate move, the leader of an IS offshoot in Bangladesh, Shaykh Abu Ibrahim al-Hanif, has previously vowed to launch "operations within Burma once we've reached the capability to do so".

"The Muslims in Burma have been oppressed by the mushrik Buddhists for a long period of time," he said in an interview with Dabiq, an IS magazine, last year.

Sorry, this video has expired Escalating violence causes 300,000 Rohingya Muslims to flee Myanmar

An Australian security expert warned that calls by Al Qaeda and IS to mobilise resources in Myanmar — while not surprising — could lead to a flow of high powered weaponry to militant Rohingyas.

"There's a number of reasonably militant groups in Bangladesh, so they may well have ways of getting weapons to the Rohingya groups," said Greg Fealy, an associate professor of Indonesian politics at the Australian National University.

"One of the things we've seen in the last month is some fightback from some of those displaced Rohingyas — attacks on police posts, military posts, in Rakhine state.

"But most of the time they've been with either sharp instruments, swords, machetes, things like that. They have very few weapons, the Rohingya attackers. So we could see a considerable escalation in the nature of the conflict.

"Because they're a very distressed community and there is great animosity towards what is happening to them in Myanmar. So that would worsen what is already a very serious situation."