Malaysian authorities have an unofficial agreement with the UN refugee agency not to place card holders in immigration detention centres, a deputy minister has revealed.

Deputy Home Minister Nur Jazlan Mohamed said this in disputing a report that refugees and asylum seekers were dying in immigration depots.

"Enforcement officers, i.e police and the immigration department have unofficially respected UNHCR's request not to arrest their card holders and put them in detention centres so there cannot be refugees recognised by them in our detention centres.

"Only illegal immigrants are detained in the centres. Those issued UNHCR cards are allowed to move freely in the country.

"In fact they have established colonies in certain parts of Kuala Lumpur, Selangor, and Pahang," Nur Jazlan said.

UK daily The Guardian today cited the UNHCR as saying that 24 refugees and asylum seekers have died in detention - mainly from disease, but also due to physical abuse in some cases.

"How does UNHCR know they are refugees? We haven't recorded any refugee arrivals by boat or under distress in the last few years.

"But they have issued a significant number of UNHCR cards to arrivals who claim to be refugees. I think they have issued cards to illegal immigrants who were arrested by immigration officers and are not refugees.

"I would dispute their claims that refugees have been mistreated in our detention centres. Anyway we are doing an exercise to find out the estimated number of refugees with cards issued by UNHCR to verify their actual status," Nur Jazlan said.

He added that there were doubts about the number of UNHCR card holders, said to total 160,000.

However he said the UNHCR "has refused to cooperate" with the Home Ministry on this exercise.

"I hope they don't have anything to hide," he said.

He also said even though Malaysia is not a signatory to the UNHCR convention, the country still cooperated with the agency out of respect tfor the UN.

"But they should reciprocate and inform us officially of any problems with refugees so that we can investigate and solve it and not talk to media," he said.

In a parliamentary reply published this month, the Home Ministry said the largest number of deaths were recorded at the detention camps located in Langkap (40), Bukit Jalil (31) and Lenggeng (28).

Most of the deceased were Myanmarese (73), followed by Indonesians (23) and Bangladeshis (14).

The Home Ministry said the deaths were caused by a range of illnesses, including tuberculosis and HIV.