Hundreds of Burundians continue to flee political instability and election-related violence just days before the country heads to the polls, the United Nations High Commissioner for Refugees (UNHCR) has said.

Massoumeh Farman-Farmaian, spokesperson for the UNHCR in Kasulu, Tanzania, told Al Jazeera on Friday that the UN agency had a plan for up to tens of thousands more fleeing neighbouring Burundi. 

"With everything happening in Burundi, we are anticipating that up to 150,000 more people could still flee Burundi and we are prepared for that," Farman-Farmaian said.

At least 127,000 Burundians have fled to neighbouring Tanzania (62,000), Rwanda (45,000), Uganda (8,855), the Democratic Republic of the Congo (10,590), and Zambia (400), with the insecurity spurring on thousands more to flee.

The UNHCR said between 200-300 refugees continue to arrive in Tanzania, and are being transferred to the Nyarugusu refugee camp, which has long been overcrowded.

"The camp is overcrowded, services are stretched and we are trying our best to accommodate all," Farman-Farmaian said.

It is understood that the UNHCR and partners were closing in on agreement with the Tanzanian government on a new camp site for new arrivals.

The camp is now home to 120,000 refugees, 'making for congested living conditions and stretching services and facilities' [Azad Essa/Al Jazeera]

As political insecurity continues in Burundi, a leading opposition candidate on Friday called for the postponement of elections until conditions to make the polls free and fair are met.

Agathon Rwasa, a leading opposition presidential contender, said elections should not be held in current conditions characterised by insecurity, lack of freedom of expression, and movement.

Burundi is scheduled to hold parliamentary elections on Monday and presidential elections on July 15. Rwasa says President Pierre Nkurunziza should withdraw his candidacy which is in violation of the constitution's two-term limit for presidents.

Rwasa says there is intimidation and assassination of opposition figures and more than 127,000 people have fled the country for fear of violence.

Burundi has experienced weeks of unrest since the ruling party's April 26 announcement that Nkurunziza will run for a third term in office.

The Nyarugusu camp in Tanzania was already home to some 60,000 Congolese refugees before the arrival of the Burundians this year. The camp is now home to 120,000 refugees, "making for congested living conditions and stretching services and facilities".

The number of arrivals had increased sharply over the last few days in Rwanda, with more than 600 refugees crossing the border each day. Around 200 Burundians were also arriving in Uganda each day.

In May, the UNHCR, along with 17 partners, launched the Regional Refugee Response Plan. The plan required around $207m to protect up to 200,000 refugees. The plan has only managed to secure 13 percent of its target so far.

Source: Al Jazeera And Agencies