The leaders are set to meet with India's Prime Minister Narendra Modi and a high-level US delegation in Port Moresby on Monday.
PNG Prime Minister James Marape told local media on Thursday that President Joe Biden had called to apologise for his absence due to the need to return to Washington for meetings with Congressional leaders to raise its debt ceiling issue and avoid a default.
"He conveyed his sincerest apologies that he cannot make it into our country," Marape said.
"I did place the invitation to him [that] at the next earliest available time, please come and visit us here."
Biden has confirmed that US Secretary of State Antony Blinken will arrive on Monday to meet with PNG for a bilateral meeting and engage in a separate meeting with the Pacific Islands Forum leaders.
Biden also invited Marape and other Pacific leaders to Washington later this year for the second US summit with the Pacific Islands Forum.
"He did invite again the Pacific Island leaders to go back for a progressive continuation of the meeting that we have initially held last September in Washington," Marape said.
RNZ Pacific reports Fiji Prime Minister Sitiveni Rabuka has already arrived in Papua New Guinea.
He was greeted by acting Deputy Prime Minister John Rosso.
"After being welcomed by young traditional Motu Koitabu dancers, PM Rabuka made a courtesy visit to Government House and met with Governor General Grand Chief Sir Bob Dadae," Rosso said in a statement.
He has since been hosted by Marape for dinner at the State Function Room at Parliament House.
"PM Rabuka will be joined by other Pacific Island leaders, including New Zealand PM Chris Hipkins, who will travel into PNG this weekend," Rosso said.
The leaders will be in Port Moresby for the third Forum for India-Pacific Islands Cooperation (FIPIC).
According to Marape, 14 of the 18 Pacific Islands Forum member leaders including New Zealand's Prime Minister Chris Hipkins are expected to be in attendance.
Fiji PM Sitiveni Rabuka is welcomed in PNG. Photo: Supplied/PNG Gov.