About 15 students, from the 'Fossil Free QUB' group, have been occupying part of the university's administration building since Friday.
A QUB spokesperson said a review of its investment policy is taking place.
The review will be completed next spring.
The spokesperson added that the university is happy to hold discussions with Fossil Free QUB, but there would be no immediate decision taken on its investment policy outside of the review.
The Green Party Northern Ireland, the Social Democratic and Labour Party (SDLP) Alliance Party, Sinn FÃ©in and People Before Profit have all expressed support for the fossil free campaign.
Belfast city Green Party NI councillor Ross Brown was at the demonstration at Queen's, and called for the university to disinvest in fossil fuels.
"There are investment indexes that exist now that exclude fossil fuels, so there's no stopping Queen's choosing those indexes and taking their money out of fossil fuels."
The Sinn FÃ©in MLA Chris Hazzard also said the university should take action now, rather than waiting for the results of a review.
"Other universities around the world, including Sheffield, have recently done this, so it's time for Queen's to do that too," he said.
Meanwhile, freedom of information requests carried out by the Fossil Free QUB organisation - and seen by the BBC - show that some of Queen's money is subsequently invested in;
However, these types of investments are not unusual, according to a wealth management expert.
Ewan Boyle, director of Johnston Campbell financial advisors, told the BBC that many organisations had diverse portfolios.
"If we look at the top 100 companies in the UK, around 25% of those have a bias towards mining or oil, so avoiding those companies if you are a large investor is virtually impossible" he said.
"Queen's are passing their money to fund managers, who are responsible for investing that money, and their primary objective is to get the best returns they possibly can."
"It's what many pension funds, and many large organisations are doing," Mr Boyle added.
"Mining and oil have been huge growth areas in recent years, so that's where the fund managers are investing to get those returns."
A Queen's spokesperson said that university business was continuing as normal, although a small number of staff in the finance office had been relocated.
A number of politicians have attended the protest calling for Queen's University, Belfast (QUB) to sell shares it holds in fossil fuel firms.