By Jonathan Kent BBC News, Kuala Lumpur

Malaysia has an uneasy relationship with its immigrants

Malaysian police have arrested a number of government officials on suspicion of selling residency permits to criminals involved in people-trafficking.

The civil servants are being held under terrorism laws that allow indefinite detention without trial or charge.

The news comes two days before the Indonesian president visits Malaysia to discuss illegal immigration.

It also comes as Malaysia is poised to expel hundreds of thousands of illegal migrants.

Interior Minister Azmi Khalid would not say how many were arrested or when the police moved in.

He confirmed that those detained were believed to have been selling permanent residency documents.

Microchip records

However, he told the BBC that press reports of a security breach involving national identity cards were untrue.

The microchip cards also contain individuals' medical records and driving licences and can be used to access bank accounts.

This is not the first time that civil servants have been accused of working with criminals.

Late last year, immigration officials were briefly investigated for freeing members of Triad gangs suspected of smuggling Chinese women into the UK.

It is also widely reported that police and immigration officers routinely extort money from illegal migrants.

President Susilo Bambang Yudhoyono arrives here for talks on Monday with the issue of undocumented Indonesian workers high on the agenda.

It appears that Kuala Lumpur wants to be seen to be putting its own house in order before those discussions begin.