Kigali - Rwanda said on Friday it wanted no part in Israel's "internal politics" after turning away two opposition Israeli lawmakers who wanted to discuss their country's controversial plan to deport African migrants and asylum seekers.

The MPs said they had come to Rwanda on a "fact-finding mission" to discuss Israel government policy to expel about 38 000 migrants who have entered the country illegally, mainly Eritreans and Sudanese.

As the migrants could face danger or imprisonment if returned to their homelands, Israel is offering to relocate them to an unnamed third country, which aid workers say is Rwanda or Uganda.

But Rwandan authorities refused to meet the Israeli lawmakers.

"Rwanda cannot be a playground for Israeli internal politics. We deal with governments and we only receive foreign officials that are announced and cleared by their foreign ministries," Foreign Affairs minister Olivier Nduhungirehe told AFP.

"If any Israeli MP has any issue with his or her government about African migrants who are in Israel, he or she should deal with the Israeli government, not ours."

The Israli government has given the migrants an ultimatum: leave by April 1 or risk being imprisoned indefinitely.

Public opposition to the plan in Israel has been slow to build, but some Israeli airline pilots have reportedly said they will not fly forced deportees.

"We are on a fact-finding mission to Rwanda because we want to ascertain the truth," Michal Rozin, an Israeli MP for the leftwing opposition party Meretz, told AFP.

"We sent out requests for meetings with Rwandan officials over the illegally planned deportation of Eritrean asylum seekers to Rwanda from Israel, but officials declined to meet us and we wonder why," she said.

Both countries have denied a secret deal to take in the migrants is in place.

The UN refugee agency has said about 4 000 migrants were deported from Israel to Rwanda between 2013 and 2017.

However only seven remain in Rwanda, according to UNHCR, with many fleeing poor conditions to neighbouring countries - particularly Uganda - or heading for Europe.

"It is clear that once the refugees are sent to Rwanda from Israel, they are not offered the basic necessities like jobs and housing that they are promised," said Mossi Raz, a Meretz MP and the other member of the Israeli delegation.

"That is why we insist that any deal that is in place to force their deportation to Rwanda should be immediately abandoned," he said.

The UN has condemned Israel's expulsion policy, which offers each migrant $3 500 and a plane ticket, as incoherent and unsafe.