The Liberal party's falling popularity extends beyond the federal level, with support for a long-term state government plunging to its lowest point in 16 years.
The Liberals suffered a convincing loss at the May 3 election under former leader Peter Dutton and on Tuesday the Nationals pulled out of their coalition agreement.
Tasmania's Liberal government is also on the nose, according to polling taken in mid-May, with a proposed new stadium becoming an "issue" with voters.
Support for the island state Liberals has dropped from 34 per cent to 29 per cent - the lowest level since 2009.
Their pet project, a new $755 million Hobart waterfront stadium as part of a contract for an AFL team, was placed equal second by voters (13 per cent) as the most important issue.
It was tied with cost-of-living and behind only health (21 per cent).
Just two per cent of voters considered the stadium an issue in previous polling.
Labor picked up two Tasmanian seats off the Liberals at the federal election and convincingly held another marginal seat.
Support for Tasmania's Labor opposition (31 per cent) has overtaken the Liberals for the first time since 2009.
However, it's a rise of just one per cent from previous polling.
Support for state-level independents went up five per cent to 17, while the Greens lifted one per cent to 14 and the Jacqui Lambie Network fell from eight to six per cent.
"It seems clear the proposed Macquarie Point stadium has become a serious drag on the Liberal vote," said Mary Massina, managing director of polling company EMRS.
"At the same time, the movement in votes from the Liberals to independents suggest Labor's ability to capitalise on this is also being held back by their support for the stadium."
Labor says it supports the stadium unconditionally after stating at the most recent state election it would try to renegotiate the AFL deal if in power.
The Liberals, who have been in power since 2014, are governing in minority with just 14 of 35 lower-house seats.
Despite his party sliding in popularity, Premier Jeremy Rockliff maintained his personal support level (44 per cent), with Labor leader Dean Winter dropping two per cent to 32.
