The United Nations has confirmed the release of all 45 Fijian peacekeepers who had been held for two weeks by the rebels in the Golan Heights on the Israeli-Syrian border.

A UN statement statement said the soldiers, all in good condition, had been freed on Thursday and would undergo medical assessment.

UN Secretary-General Ban Ki-moon welcomed their release and, according to a spokesman, demanded that all parties in the area respect the UN force's "mandate, freedom of movement and the safety and security of its personnel."

The Fijians were kidnapped last month by the Nusra Front battling the Syrian army after the rebels overran a crossing point in the so-called disengagement zone that the UN peacekeeping mission known as UNDOF has monitored since 1974.

An Israeli military spokeswoman said the soldiers had crossed into Israeli-held territory after their release.

"We opened the border and they entered," the spokeswoman said.

On Wednesday the Nusra Front posted a video on its Twitter and YouTube accounts in which the hostages said they expected to be freed soon.

The Fijians had been captured about 8km away from 70 Philippine troops, who were rescued following an attack on their post on the Syrian side of the border.

Syria's three-year civil war reached the frontier with Israeli-controlled territory last month when rebel fighters overran a crossing point in the line that has separated Israelis from Syrians in the Golan Heights since a 1973 war.

Syria and Israel technically remain at war. Syrian troops are not allowed in an "area of separation: under a 1973 ceasefire formalised in 1974.

The UN force monitors the area of separation, a narrow strip of land running about 70km from Mount Hermon on the Lebanese border to the Yarmouk River frontier with Jordan.

It comprises 1,223 soldiers from Fiji, India, Ireland, Nepal, Netherlands and the Philippines.

The head of Fiji's army said on Wednesday the armed group had dropped all of its earlier demands.

A UN spokesman said in New York on Thursday no ransom had been requested for the Fijian peacekeepers and none was paid. He said the UN mission in the region remained viable and would continue to fulfil its mandate.

Austria, Japan and Croatia have all pulled their troops out of the monitoring force due to the deteriorating security situation and spillover from the Syrian war.

Qatar, one country in the Middle East thought by the US to have influence with the armed rebel group, said Fiji had formally requested its assistance in freeing the hostages.

US officials have said that Qatar played a critical role in persuading the Nusra Front to free American journalist Peter Theo Curtis last month, whom the front had been holding hostage since 2012.