In a dramatic show of defiance Myanmar's Permanent Representative Kyaw Moe Tun has denounced his country's military regime before the General Assembly and declared he would fight for democracy.

"We will continue to fight for a government which is of the people, by the people, for the people," he said during an Assembly session on Myanmar.

His speech won a round of applause from diplomats who were at first astounded by his public break with Myanmar's military government that jailed State Counsellor Aung San Suu Kyi and other leaders this month and declared the election won by their National League for Democracy invalid.

Tun said that his loyalty was to the elected government of Aung San Suu Kyi and was speaking on behalf of the democratically elected members of parliament.

He called for "strongest possible action from the international community to immediately end the military coup, to stop oppressing the innocent people, to return the state power to the people and to restore the democracy".

"It is time for the military to immediately relinquish power and release those detained," he said.

He raised his three fingers in a salute that has become a symbol of the Myanmar protesters demanding a return to democracy.

UN's Special Envoy Christine Schraner Burgener told the Assembly through a video link that the situation in Myanmar was "fragile" and had not yet stabilised.

The military's takeover remained only a "coup attempt" and the international community should "not lend legitimacy or recognition to this regime" because "it would appear to be roundly rejected by the people".

"If there is any escalation in terms of military brutality — and sadly as we have seen this before in Myanmar — against people exercising their basic rights, let us act swiftly and collectively", she added.

India's Permanent Representative said that New Delhi was "deeply concerned that the gains made by Myanmar over the last decades on the path towards democracy, should not get undermined.

He said, "Restoring democratic order should be the priority of all stakeholders in Myanmar. The international community must lend its constructive support to the people of Myanmar at this critical juncture."

Secretary-General Antonio Guterres's Spokesperson Stephane Dujarric was asked at his briefing about the danger to Tun and his family because of his speech at the Assembly.

He said, "No one should be harmed. No one should be thrown in jail for expressing their opinion. …Families should not be punished for the actions of another member. There needs to be freedom of expression, freedom of assembly, and there hasn't been. And we've been very concerned about that."