Prospects of release of Muhammad Haneef brightened on Friday, after the Australian police dropped a request to extend the detention of the Indian doctor who has been in custody for 11 days without charge in connection with the failed terror plot in the UK.

The Australian Federal Police quickly resumed interrogation after it withdrew its application to a Brisbane magistrate to prolong the detention, which ends on Friday, amid reports that it has not been able to find any incriminating evidence against Haneef.

The police now have 12 hours excluding usual breaks like meals to probe the 27-year-old doctor under counter-terrorism laws before he must be charged or released soon.

But the 12-hour period could stretch to one or two days since fresh questioning would not be done in one go.

Haneef's lawyer Stephen Keim said he expected the questioning to be complete in around 24 hours while another lawyer Peter Russo said in a worst case scenario the doctor could be held for three more days.

Current documents circulated by senior public servants in the Howard Government show the AFP acknowledges  it has scant or no evidence against Haneef and cannot test his knowledge without any incriminating evidence.

The police move not to press for detention came amid growing calls in Australia for releasing Haneef immediately with the Law Council saying the 'law was not operating fairly in Haneef's case'.

Australian Prime Minister John Howard however said he was not uncomfortable with the extended detention of Haneef.

"I'm not calling him a terrorist, I'm not passing a judgment on him," he said.