It has published a picture on the social network showing off its numbers as it continues the drive to remove the government led by Marape.
A week ago, it looked like Papua New Guinea's Prime Minister was about to lose his job after a mass revolt — but in a surprise twist, he has managed to take control of Parliament, and suspend it for five months, the Australian Broadcasting Corporation reports.
A week is a long time in politics, especially in Papua New Guinea. But it's not over yet.
What started with the shock defection of dozens of Government ministers and MPs to the Opposition, is now going to the country's Supreme Court.
When PNG's Parliament opened last Friday, more than half of the members were missing and several Government benches were notably empty.
Around 10 minutes into the session, the Opposition dramatically entered the chamber, with dozens of Government ministers and MPs among their ranks.
It became clear a push to oust Marape was under way as speculation had been swirling for months about dissent in government ranks, but the shift was sudden.
Opposition Leader Belden Namah claimed 61 of the Parliament's 111 members were now in his camp, and that "as far as the numbers are concerned, the new government is here".
Despite calls from the Opposition for him to resign, Marape dug in, saying he believed he could get enough MPs to return to his team before a vote of no confidence in December.
The disgruntled ministers and MPs who crossed the floor have offered a range of reasons for doing so.
Concerns over PNG's troubled economy, which was struggling before the pandemic and has only worsened since, have been a major factor cited by many.
Marape came to power promising to get a bigger slice of resources revenue and to make PNG the "richest black Christian nation", but progress toward that lofty goal has been slow.
One of these was the government's ill-faith negotiations, then closure of the Porgera gold mine in Enga Province, which has been criticised by the opposition.
Porgera mine stopped operating in April after the Marape government refused to renew operator Barrick Niugini's lease — the profitable mine produced more than eight tonnes of gold last year.
"Over 80% of our economy depends on the resource sector, when you mismanage that the economy obviously suffers," the former prime minister Peter O'Neill said.
Marape's remaining MPs passed the Budget as there was no one to oppose it, and parliament was suspended until April next year.
If the Opposition's Supreme Court challenge is successful, parliament could be back in December.
Either way, a vote of no confidence in Marape will still be possible: the main difference will be how long each side gets to bolster their numbers before Parliament returns.
For the moment, Marape is remaining in the top job, and he is saying "it's business as usual".
But he still doesn't appear to have a majority of the 111 members. When his team returned to Parliament, there were only 50 MPs.