Israel 'coercing Eritreans and Sudanese to leave'
Earlier this year, African asylum seekers in Israel staged mass protests over their treatment.
Israel says its policies on illegal immigrants and refugees comply with international law.
It insists that the Africans are not asylum seekers but economic migrants who see Israel as an attractive destination because it is the nearest developed country where they can find jobs.
'Illegal infiltrators' Eritreans and Sudanese began arriving in Israel through Egypt's Sinai Peninsula in large numbers in 2006. By December 2012, about 37,000 Eritreans and 14,000 Sudanese had entered the country.
Israeli interior ministryThe growth in infiltrators from Israel leaving of their own free will that stands at three times the amount in 2014 than in contrast to 2013 proves that this policy bears results”
In September 2013, the Israeli Supreme Court ruled that a 2012 amendment to an anti-infiltration law, which allowed for the indefinite detention of people for illegal entry, was unlawful.
In response, the Israeli parliament passed another amendment to the law in December that established the Holot facility in the remote Negev desert for those considered "infiltrators".
Hundreds of Eritreans and Sudanese have since been ordered to report to the centre, where they live in conditions that HRW says breach international law on arbitrary detention.
The Israeli authorities say they are not detained because they can leave for a few hours at a time. However, they are required to report three times a day and to be in the centre at night. The only way for them to secure their release is to be recognised as a refugee or leave the country.
In February 2013, Israel allowed Eritreans and Sudanese to lodge asylum claims in significant numbers. However, as of March 2014, the authorities had only reviewed slightly more than 450 "detainee" cases, and the rejection rate has been almost 100%, HRW says.
"Eritreans and Sudanese in Israel are left with the choice of living in fear of spending the rest of their days locked up in desert detention centres or of risking detention and abuse back home."
HRW says Israel is violating the international principle of "non-refoulement", which forbids states from returning refugees and asylum seekers to places where their lives or freedom would be threatened.
In response to the report, the Israeli foreign ministry said: "Israel treats illegal migrants entering its territory in accordance with international law, including the UN treaty on refugees.
"Illegal migrants are able to file a request to be granted the status of refugees, and can also appeal the decision by the Israeli authorities regarding their status to the Israeli courts," it said.
Migrants had not been expelled, the statement said, adding that those who had left had chosen to do so "of their own free will".