Bodies wrapped in shrouds lay in rows as mourners gathered, with witnesses saying many of those killed were women and children.
Around 40 people remained missing under the debris, the civil defence agency said.
Its spokesman, Mahmud Bassal, described the complete destruction of a five-storey home, adding that the area lacked medical facilities to treat the wounded.
“The number of martyrs in the massacre of the Abu Nasr family home in Beit Lahia has risen to 93 martyrs, and about 40 are still missing under the rubble,” he told AFP.
The Israeli military said it was “aware of reports that civilians were harmed today (Tuesday) in the Beit Lahia area”.
“The details of the incident are being looked into,” it told AFP. “We emphasise that the area was evacuated by the IDF (Israeli army) and it is currently an active combat zone.”
One witness, 30-year-old Rabie al-Shandagly, said most of the victims were women and children.
“People are trying to save the injured, but there are no hospitals or proper medical care,” said Shandagly, who had taken refuge in a nearby school.
“The explosion happened at night and I first thought it was shelling, but when I went out after sunrise I saw people pulling bodies, limbs and the wounded from under the rubble,” he told AFP.
‘The civil defence agency spokesman said: “This morning, a five-story house was targeted, completely destroying it and wiping out entire families from the civil registry in this house”.
“There are dozens still under the rubble. We do not have crews or any services to provide to the citizens there,” said Bassal.
“We receive distress calls from citizens around the clock in various areas of Jabalia, Beit Lahia and Beit Hanun after the targeting of citizens’ homes.”
Hamas, which is locked in war with Israel in Gaza, condemned the Beit Lahia attack.
“The enemy has committed another horrific massacre against our people, and northern Gaza is being subjected to a campaign of ethnic cleansing and systematic displacement,” Hamas said.
The bodies of 15 people killed in the strike were brought to Kamal Adwan Hospital, which said it was overwhelmed and facing severe shortages of staff and supplies.
The hospital’s director, Hussam Abu Safia, said 35 wounded people, most of them children, were being treated at the facility.
“We are still receiving a number of martyrs and wounded,” Safia said.
“There is nothing left in the Kamal Adwan Hospital except first aid materials after the army arrested our medical team and workers when they invaded the hospital during the military operation in Jabalia,” the director said.
Last week, the Gaza health ministry said Israeli troops had stormed the hospital, while the Israeli military said it was operating around it.
The World Health Organization said its teams managed to return to Kamal Adwan Hospital on Monday and provided information about the situation there.
“They have found one orthopaedic surgeon, one paediatrician, a chief nurse and a handful of young doctors, and junior doctors and nurses try to attend to some 100-150 patients,” WHO spokesman Tarik Jasarevic said.
“This shows how difficult it is to provide any sort of aid in north Gaza,” he told reporters in Geneva.
Since October 6, the military has conducted a sweeping air and ground assault in northern Gaza, particularly in the areas of Jabalia, Beit Lahia and Beit Hanun.
Tens of thousands of Palestinians have been forced to flee northern Gaza since the onslaught began, while the civil defence agency has reported hundreds of deaths.