A granddaughter of Gaza's Hamas Prime Minister Ismail Haniyeh has returned home "clinically dead" after Israeli physicians who treated the child said they were unable to save her.

One-year old Amal Haniyeh was hospitalised in a serious condition at the Schneider Children's Medical Centre in Petah Tikvah, reportedly due to an infection in her digestive tract.

Local reports said Israeli doctors determined she could not be treated and declared she had slim chances of survival.

"I call on God to grant good health to my daughter Amal, who entered in a state of clinical death," Hamas prime minister's son Abdessalam Haniya wrote on his Facebook page, according to the AFP.

The Israeli defence ministry said a one-year-old girl had crossed from Gaza to Israel for treatment in critical condition, but it did not divulge specifics.

Palestinians have posted pictures of Hamas premier visiting his granddaughter in a Gaza hospital.

A relative of the prime minister told the Associated Press, on condition of anonymity, that the incident had "no political significance".

Although Israel and Hamas are bitter foes, scores of people from the Gaza Strip usually receive medical treatment in Israel.