With the police custody of Indian doctor Mohammed Haneef detained in connection with the foiled terror plot in the UK coming to an end on Wednesday, Australian investigators on Tuesday said they might need to hold him for some more time to glean through the evidence gathered in a series of raids.

Lawyer for the Gold Coast-based Haneef, meanwhile, said he may launch an appeal against the continued detention of his client.

Haneef's brother Shoaib also hit out at Australian investigators for holding him without charge and for raising suspicions about his transfer of funds.

Federal Attorney General Philip Ruddock and Australian Federal Police Commissioner Mick Keelty said police will ask a magistrate for a further extension of time to detain Haneef, if necessary.

On an AFP officer being sent to India, Federal Attorney General Philip Ruddock said, "I welcome the cooperation that has been provided to the AFP."

Police custody of the Indian doctor was extended till Wednesday by a Brisbane court, which turned down a police appeal for extending his detention for five more days.

Haneef, 27, has been in detention for more than a week without charge in connection with the investigation into the failed terror attacks.

A request for more time would depend on how the investigation proceeded.

"They sought an extension of time and that doesn't preclude them seeking further extensions of time," Ruddock said adding, "It depends on whether they believe it is necessary as part of their investigation."

Ruddock said the probe should be comprehensive. "We want the investigations to be thoroughly professionally carried out and I would think Haneef would want the same outcome. He would want to be exonerated as a result of the inquiries and he would want them to be full and complete."

Keelty said police was applying the law as it was available to them."We asked for a period of time that we thought was reasonable in terms of the amount of work that we envisage needs to be done."

"If it's required we will go back to the magistrate. What we're doing here is applying the law that we operate under in these circumstances," Keetly added.

Meanwhile, a report in The Australian newspaper said that senior police officials were concerned about the investigative team's failure to conduct a "full forensic" of Haneef's Gold Coast unit before Sunday.

The AFP allowed managers of the Telesto complex where Haneef lives to enter and clean his unit on Thursday -- two days after the initial raid, but before more thorough searches and forensic examinations were conducted during the weekend.

Meryl Bosher, who manages the complex with her husband Steve, said on Monday night that they had washed, dried and put away dirty dishes, and removed bread and fruit that had been left out on the counter.