Key senior MPs, including deputy prime minister Sam Basil, crossed the floor last week to join PNG's opposition.
Marape has said on Facebook they were within their rights to do so but in the meantime he remained prime minister and had fought for a greater return from the country's resources, including from Porgera.
Barrick Nuigini (BNL) said this week "patently false statements" made by certain individuals linking Bristow's latest visit to the political manoeuvring were designed solely to create a fictitious narrative about BNL's role to further their own political agenda.
"Those defamatory and entirely false posts have been reported to PNG authorities requesting appropriate action, and have also been reported to Facebook," BNL said.
"Mr Bristow and his team travelled to PNG in good faith under a joint agreement between prime minister Marape and Mr Bristow, which committed to negotiations relating to the restart of the Porgera mine.
"During his recent visit, Mr Bristow and his team did not meet with anyone other than prime minister Marape, together with several of his ministerial colleagues, Enga governor Peter Ipatas, members of the state negotiating team, and the Porgera landowners and their team."
Bristow and Marape also held talks in October discussing the path to reopening Porgera.
The mine has been mothballed since April, after PNG refused to extend a special mining lease (SML), with BNL challenging both the refusal and PNG's August decision to award an SML to state-owned Kumul Minerals Holdings.
Porgera is owned 47.5% by both Barrick and Zijin Mining, with the remaining 5% held by the Enga provincial government and landowners.
Barrick has withdrawn 2020 guidance for Porgera, which last year produced 284,000 ounces of gold at all-in sustaining costs of US$1003/oz for the Canada-based company.