The Scottish Green party has made a direct appeal to the Liberal Democrats to form a coalition with the SNP.
Alex Salmond is still struggling to form a government, as Labour increasingly position themselves as a back-up administration if Mr Salmond is unable form his own.
The Liberal Democrats have so far rejected SNP advances to form a coalition, citing an objection to the nationalists' manifesto pledge to hold a referendum on independence.
However, the Greens - who have confirmed their intent to work with the SNP, even if only on an issue-by-issue basis - have now called on the Liberal Democrats to reconsider their position.
Robin Harper, Green party co-convener, said the party has enjoyed "positive" talks with the SNP after agreeing to support a nationalist government.
Arguing that the "uncertainty" over the Lib Dem position must be resolved, Mr Harper appealed to the party's leadership to meet with the Greens tomorrow to discuss a possible deal between the SNP, Greens and Lib Dems.
Mr Harper said: "This is a last chance for the Liberal Democrats to make up their mind. We understand their position about the referendum, but there is so much else at stake over the next four years.
"The reality is that both the SNP and the Greens will have to accept that there is no majority in the parliament for such a referendum.
"However, nothing should stand in the way of any parties seeking to address climate change and social justice. Liberal Democrat voters would expect them to approach these issues in a constructive manner."
As the pro-independence SNP struggle to overcome the barriers to coalition talks, Labour leader Jack McConnell has continued to argue an SNP government is not inevitable.
Mr McConnell claims Labour will form an administration if Holyrood does not approve a minority SNP government.
Although it is expected MSPs will vote for Mr Salmond as first minister, Labour are expected to attempt to pass bills even if they do not form an administration. Backing from the Lib Dems on an issue-by-issue basis could give them the support to enact legislation.
Holyrood has until the end of the month to approve an administration. If it is unable to do so, the Scottish people will automatically return to the voting booths to select a second round of MSPs.