Families of Israeli hostages were informed on Wednesday of the names of those due to be released later in the day, Israel's public broadcaster Kan reported, the final group to be freed under the truce unless negotiators succeed in extending it.
So far Hamas, the militant group ruling the Gaza Strip, has freed 60 Israeli women and children from among the 240 hostages they seized in a deadly rampage on October 7 under the deal that secured the war's first truce.
Twenty-one foreigners, mainly Thai farm workers, were also freed under separate parallel deals. In return, Israel has released 180 Palestinian security detainees, all women and teenagers.
The penultimate release on Tuesday included for the first time hostages held by Islamic Jihad, a group allied to Hamas, as well as by Hamas itself.
The initial four-day truce was extended by 48 hours from Tuesday, and Israel says it would be willing to prolong it further for as long as Hamas frees 10 hostages a day.
But with fewer women and children still in captivity, that could mean agreeing to terms governing the release of at least some Israeli men for the first time.
Israel has released 180 Palestinian security detainees, all women and teenagers, under the deal. (EPA PHOTO)
A Palestinian official told Reuters that despite a willingness on both sides to prolong the truce, no agreement had yet been reached. Discussions were still under way on Wednesday with mediators Egypt and Qatar, the official said.
Israeli Prime Minister Benjamin Netanyahu's office declined to comment on the state of any talks but noted that an extra 50 Palestinian women detainees had been added on Tuesday to a list cleared to be released in case a new swap was agreed.
The truce has brought the first respite to a war launched by Israel to annihilate Hamas after the "Black Sabbath" raid by gunmen who killed 1200 people on the Jewish rest day, according to Israel's tally.
Israeli bombardment has since reduced much of Gaza to a wasteland, with more than 15,000 people confirmed killed, 40 per cent of them children, according to Palestinian health authorities deemed reliable by the United Nations.
Many more are feared buried under the ruins. The Palestinian health ministry said another 160 bodies had been pulled out of rubble during the past 24 hours of the truce, and about 6500 people were still missing.
On Tuesday, mediator Qatar hosted the spy chiefs from Israel's Mossad and the US CIA.
The officials discussed possible parameters of a new phase of the truce deal including Hamas releasing hostages who are Israeli men or soldiers, a source briefed on the matter said. They also considered what might be needed to reach a ceasefire lasting more than a handful of days.
The truce has brought the first respite in the war in Gaza after weeks of bombardment. (AP PHOTO)
Qatar spoke to Hamas before the meeting to get a sense of what the group might agree to, and the opposing sides are now internally discussing the ideas explored at the meeting, the source said.
There was no immediate word on whether the final group to be freed on Wednesday would include the youngest hostage, 10-month-old baby Kfir Bibas, held along with his four-year-old brother and their parents.
Relatives had come forward with a special plea after they were omitted from the penultimate group freed on Tuesday.
The truce has held throughout the six days despite reports from both sides of comparatively small-scale violations, though both say they are prepared for war to resume with full intensity the moment it lapses.
A spokesperson for Israel's military said the truce was still holding on Wednesday. Palestinians accused Israeli forces of firing at homes near the beach in Khan Younis from the sea, and of shooting in Beit Hanoun in northern Gaza.
