Indian doctor Mohammed Haneef, detained in connection with the failed UK terror plots, continued to be questioned by Australian police and a British counter-terrorism official in Brisbane on Saturday.

Haneef, who worked as a registrar at the Gold Coast Hospital, was detained by police at Brisbane airport on Monday as he allegedly attempted to leave the country on a one-way ticket.

Police have been granted a legal extension to detain the doctor for questioning until 11.30 pm local time Monday night.

The so called 'dead time' provisions allow police a custodial pause.

The Australian police along with a British counter-terrorism official continue to interrogate Haneef.

An Australian Federal Police spokeswoman, however, said on Saturday that there had been no fresh development in the case.

Haneef is reported to be the cousin of brothers Sabeel and Kafeel Ahmed, two of the key suspects in the terror plots in London [Images] and Glasgow.

Federal police is sifting through more than 31,000 documents - some in foreign languages - seized in raids on Friday on two West Australian hospitals.

Five migrant Indian doctors working in Western Australia and New South Wales were also questioned by police on Friday as part of the widening probe into the botched terror plots.

At least one of the Western Australia doctors questioned on Friday lived in Britain before moving to Australia, the media said on Saturday.

They now work at Royal Perth Hospital and Kalgoorlie Regional Hospital in Goldfields, 600km east of Perth.

"It is quite a complex investigation and the links to the UK are becoming more concrete," Australian Federal Police Commissioner Mick Keelty said on Friday.

While a larger number of people were being interviewed it did not mean they were all suspects, he said - "Nobody has been arrested at this point of time."

It also emerged on Friday that two suspects -- the brothers Sabeel Ahmed and Kafeel Ahmed -- sought jobs in the Queensland health system as well as in Western Australia's.

Sabeel Ahmed registered his interest through the Queensland Health website on April 5 last year but was told he did not have enough experience nor did he meet the English-language requirements.

On June 30 last year, the department also had contact from Kafeel Ahmed, who is accused of driving the Jeep Cherokee packed with petrol and gas canisters into the Glasgow airport terminal.

However, he was also told to gain more experience in Britain.

Kafeel Ahmed is not a doctor, and Queensland Health was unable to list the qualifications provided to the website.

Mohammed Asif Ali, the associate of detained doctor Mohamed Haneef, who was interviewed by police but released without charge, was unsuccessful with a West Australian application in January last year but gained enough experience in Britain to be registered in Queensland in October.

The Australian Doctors Trained Overseas Association estimates there are 20,000 doctors practising in Australia who earned their original qualifications overseas -- about 40 per cent of all 50,000 doctors in Australia.

The association estimates the number of doctors in 'area-of-need' positions, which means they can perform supervised work only, to be 5000-7000.