The English Community Care Association has issued a legal challenge to the government's interim cap on non-European immigration, saying it will damage the care sector.
The cap will put continuity of care at risk by preventing many existing migrant care workers from retaining their jobs, while preventing others from entering to fill gaps, said the umbrella body for independent care providers.
Its application for judicial review, which is due to be heard in the High Court next month, claims the government failed to consult or follow proper parliamentary procedure before implementing the interim cap in July.
Under the points-based system introduced by the last government, senior care workers were listed as a shortage occupation, enabling providers to recruit from outside Europe to fill these posts.
However, the interim cap - which will be replaced by a permanent limit on annual immigration from outside Europe in April 2011 - restricts the number of senior carers who can fill posts or existing staff who can renew permits to work.
"The home secretary and the government have introduced policies which once again are detrimental to the social care sector and these steps have been taken with complete disregard for care providers and the invaluable staff they employ," said chief executive Martin Green.
The government had acted "unlawfully, unfairly and irrationally" and the sector will be disproportionately hit because of its reliance on skilled workers from outside the EU, said Kashif Majeed, of Ashton Brooke Solicitors, which is representing ECCA in its challenge.
Councils have already warned that similar restrictions on children's social workers would weaken child protection teams, putting vulnerable children at risk.
The government is already facing a legal challenge against its interim cap from the Joint Council for the Welfare of Immigrants.
In response to the JCWI's challenge, immigration minister Damian Green said: "We will rigorously defend this challenge and are confident of success. We are fully committed to reduce the level of net migration back down to the levels of the 1990s - tens of thousands each year, not hundreds of thousands."
A consultation on how the permanent limit would operate closed on 17 September.
Source: Community Care