The women at Yarl's Wood are protesting over treatment at the site
An MP is demanding an inquiry into a hunger strike by women at a holding centre for immigrants in Bedfordshire.
A dispute at Yarl's Wood Centre began three weeks ago when 50 women protested at being held for up to two years.
Labour MP for Hayes and Harlington John McDonnell has tabled a House of Commons motion, calling on the Inspector of Prisons to hold an investigation.
The Home Office said all detainees "are treated with dignity and respect, with access to legal advice".
Mr McDonnell wants an inquiry into reports of violence, mistreatment and "racist abuse" which the centre denies.
He claims some of the women involved in the protest were held in a hallway for more than five hours, denied access to toilets and water, and locked out in the cold.
Fellow Labour MP Jeremy Corbyn, who represents Islington North, has called for a halt to any removals and deportations of the women involved while an inquiry is carried out.
He has also signed the House of Commons motion.
David Wood, director for criminality and detention, said: "All detainees are treated with dignity and respect, with access to legal advice and heath care facilities.
"A small group of around 20 women are currently considered as food refusers. This means they have missed three consecutive meals in the canteen.
"However, there are alternate food arrangements within the centre, such as shops and vending machines."
Home Office minister Meg Hillier said: "While some detainees are refusing formal meals from the canteen, they are buying food from the centre's shop.
"They are all also drinking. Everyone is being assessed by medical staff and at the moment there is no cause for concern.
"The well-being of detainees is of paramount importance to the UK Border Agency, which is why healthcare staff and independent monitors... were at the scene.
"The demonstration remained passive at all times and there was no use of force."