A nine-year-old Irish-Israeli girl was among the latest group of hostages released by Hamas fighters on Saturday, Ireland's prime minister said in a statement.

"This is a day of enormous joy and relief for Emily Hand and her family," Leo Varadkar said.

"An innocent child who was lost has now been found and returned, and we breathe a massive sigh of relief. Our prayers have been answered."

Emily was one of about 240 people snatched by Hamas gunmen when they broke through Gaza's militarised border with Israel on October 7, killing about 1,200 Israelis and foreigners, according to Israeli authorities.

Following the deadliest attack in its history, Israel launched an air, artillery, and naval bombardment alongside a ground offensive to destroy Hamas, killing nearly 15,000 people, mostly civilians and including thousands of children, according to the Hamas government in Gaza.

Hamas on Saturday released a second group of Israeli and foreign civilians it had been holding hostage in the Gaza Strip in exchange for Palestinian prisoners.

Israeli authorities said 13 Israelis and four Thai citizens had returned to Israel.

The exchange came after an hours-long unexpected delay that set nerves on edge.

Emily turned nine earlier this month while being held captive.

Her father Thomas Hand, who was born in Ireland and later moved to Israel, told AFP earlier this month that initially he thought his daughter had been killed in the attack.

"Later on we had an eyewitness… (who) saw her being led away by the terrorists, into a van off to Gaza" after the attack on the Beeri kibbutz, he said.

Varadkar said he hopes Emily "will soon heal and recover from the traumatic experience in the loving embrace of her family".

"Emily now returns to her family, but we cannot forget that many more hostages remain in captivity in Gaza.

"Their fate is unknown, but we hope that like Emily, they will also be allowed to return to their homes and their families," he added.