French rescue workers searching Sulawesi in Indonesia say they have detected a person still alive in the rubble of a hotel, nearly a week after a deadly earthquake and tsunami hit the country.

High-tech sensors used by the French organisation Pompiers de l'urgence "detected the presence of a victim" on Thursday in the remains of the Hotel Mercure in Palu.

Philip Besson from Pompiers de l'urgence said: "We used a search scanner that uses a WiFi network to detect ventilator movement or cardiac motion of people who are alive, whether they are conscious or not.

"Our scanner has detected the presence of a victim here inside the hotel, so we started to drill the concrete to verify and access the victim, and to be able to check with a camera that we brought with us that will allow to have a real time knowledge of what's inside the rubble."

A rescue worker at the hotel. Credit: AP

The only equipment they had access to was a hand drill which was not strong enough to reach the victim due to the thickness of the concrete and digging had to be curtailed at nightfall on Thursday. The rescue team plan to start again on Friday with heavy duty machinery.

Nita Hamaale, whose sister works at the hotel and is missing, told AP: "I hope that the rescue is quick to find my sister and the other friend because they are staff of Mercure Hotel. And I hope the best for my sister.

Asked if she still believed that her is alive, Ms Hamaale said: "Yes, I believe, I believe my God is save (has saved) my sister and I hope my sister is alive. I hope like that."

More than 1,400 have been confirmed dead since the powerful earthquake and tsunami struck on Friday, and that number is expected to rise.

Extra troops are to be drafted in to help with the search and rescue operations, as well as keep the peace among survivors. Many have travelled to Palu's badly damaged airport hoping to take a flight away from the area.

Personnel from aid agencies are trying to get the requisite food and medicine into Indonesia to help survivors. It is estimated that 200,000 people are in need of assistance in the country.

Now that machinery has been brought to the area, workers hope to restore power by fixing broken substations.