Washington: Around 1,000 families who were reunited after being separated as part of the US administration's approach to undocumented immigrants have standing deportation orders, the government has said.

At a court hearing in San Diego, lawyers for the Department of Justice (DoJ) said that 392 families remained in the custody of immigration authorities, while the rest had been freed, albeit with electronic ankle monitors.

DoJ lawyer Sarah Fabian added that 650 minors were ineligible to be reunited with their families, including 431 whose parents are no longer in the country.

In accordance with judge Dana Sabraw's order, the US government had until July 26 to reunite 2,551 undocumented minors, aged five to 18, with their parents.

Authorities confirmed on Thursday that over 1,800 families that were considered eligible had been reunited.

Following a complaint by the American Civil Liberties Union (ACLU), the judge said he would rule that immigrant families not be deported until they had been reunited for at least seven days.

The ACLU has said that immigrant families need more time to decide whether to begin the long and complicated migration or asylum process in order to stay in the US or return to their home countries.