Johnson told members of his Conservative Party earlier this week that British investors had a "brilliant vision" to turn Sirte into the next Dubai if bodies could be cleared.
The committee for foreign affairs and international cooperation of Libya's House of Representatives (HOR) denounced the comments on Sirte as "unacceptable," adding that "it considers it a violation of Libyan sovereignty to talk about British businessmen investing there."
"The committee demands a clarification from the British prime minister and an apology to the Libyan people," the statement said.
Johnson's comments led to calls for his resignation from domestic political opponents.
He accused them of playing politics, saying on Twitter that he had been referring to the clearing of booby trapped bodies of Daesh militants.
Local Libyan forces backed by US airstrikes fought for more than six months last year to oust militants from Sirte, which the extremist group had turned into its most important base outside the Middle East.
The coastal city of about 80,000 was badly damaged during the campaign and is struggling to rebuild.
The HOR has been based in eastern Libya since 2014 when a conflict in Tripoli led to the setting up of rival parliaments and governments in the capital and the east.
Its cooperation is considered crucial for the progress of a new UN plan to stabilize Libya.
The government in Tripoli declined to comment on Johnson's remarks.
On Wednesday, gunmen killed at least four people and wounded nearly 40 on Wednesday in a suicide attack on a court complex in the Libyan city of Misrata, officials and a witness said.
Daesh claimed responsibility for the attack, saying in a statement run by the group's Amaq news agency it had targeted "one of the most prominent strongholds" of the GNA.
The attack shows the enduring militant threat in Libya after a Misrata-led coalition under nominal GNA command battled for more than six months last year to oust Daesh from its former stronghold in Sirte, about 230 km southeast of Misrata.
Since then, militants have been trying to regroup in the desert south of Sirte. They have stepped up their presence in remote areas, though attacks in urban centers have been rare.
Wednesday's attack was launched by several assailants who drove up to the complex in central Misrata in a black vehicle, a witness said. "One of them blew himself up at the gate and the other two with Kalashnikovs opened fire at random," he said.
"Shooting could be heard all over the city centre after the attack."
The witness said he believed the attackers had used rocket propelled grenades.