The wife of the Israeli prime minister has protested over a decision by her husband's cabinet to deport 400 children of migrant workers, adding her voice to an emotional debate about the nature of the Jewish state.

Sara Netanyahu wrote a letter to Eli Yishai, the hardline cabinet member in charge of the deportation programme, appealing for a review of the controversial decision, which is backed by her husband, Binyamin Netanyahu.

"I appeal to you as a mother of two young boys and a psychologist in the public service," wrote Mrs Netanyahu. "I am asking you, from the bottom of my heart, to ... allow the vast majority of the 400 remaining children to stay in Israel."

The Israeli cabinet voted two weeks ago to deport the children. In a statement following the decision, the prime minister said: "On the one hand, this problem is a humanitarian problem. We all feel and understand the hearts of children. But on the other hand, there are Zionist considerations and ensuring the Jewish character of the state of Israel." The cabinet, he said, did not want to "create an incentive for the inflow of hundreds of thousands of illegal migrant workers".

Israel has encouraged thousands of foreign workers to take jobs in its construction, agricultural and service industries in the past 10 years, since it barred most Palestinians in the West Bank and Gaza from employment inside Israel.

Some of the foreign workers – largely from south-east Asia, China and Africa – have overstayed their visas and settled to rear families. Some also entered illegally.

The government estimates there are currently 1,200 children born to around 200,000 migrant workers. After debating the issue for about a year, it decided two weeks ago to allow 800 who have lived in Israel for more than five years, speak Hebrew and attend school to remain; the rest – most of whom are less than five years old – will be deported to their parents' home countries.

Yishai, a member of the ultra-Orthodox rightwing Shas party, rejected Mrs Netanyahu's appeal. Earlier he accused migrant workers of using their children as "human shields". "The foreigners came to Israel, some of them illegally, and gave birth to illegal children here," he said.

Following the decision, defence minister Ehud Barak – who was absent from the cabinet vote – publicly dissented. "The state of Israel cannot expel hundreds of children," he said. "It is not Jewish or humane and will scar the entire Israeli society." An umbrella organisation of Holocaust survivors also objected. "The state of Israel is ... founded on a Jewish heart and conscience," it wrote in a letter to the prime minister. "We who experienced the Holocaust were witnesses to the death camp selection and the separation between children and their parents ... We are overcome by a sense of suffocation and shame."

Several thousand people demonstrated against the move in Tel Aviv at the weekend.

The children are scheduled to be deported at the end of the month.