Findings from the poll suggest the Liberal Democrats are the most popular party among GPs heading into the 12 December general election.
With less than a month to go until polling day, just 19.8% of 494 GPs who responded to the latest GPonline opinion survey said they planned to vote Conservative at the next general election - down from 30.1% who did so at the last election.
Support for Labour was only marginally higher, with 21.2% of GPs who took part in the survey saying they planned to vote for the party, compared with 31.3% who voted Labour in 2017.
Nearly a third of GPs (31.4%) said they planned to vote Liberal Democrat on 12 December, a sharp increase from 18.5% who said they voted for the party at the last general election.
Despite the decline in support for Labour among GPs, the party remains by some distance the one GPs are most likely to believe will look after the NHS. Asked 'which political party do you think can be trusted most to look after the NHS', 29.6% said Labour, 20.2% said Liberal Democrat and just 13.6% chose the Conservatives.
A total of 30% of respondents, however, chose 'none of the above' - reflecting significant disillusionment among the profession with all political parties. One in 10 GPs who took part in the survey said they did not plan to vote in the upcoming general election.
Many more were undecided about who to vote for - nearly 11% of respondents selected 'other' to indicate that they did not plan to vote for one of the main parties. Although some of these GPs planned to vote for smaller parties or independents, many suggested they had yet to choose how to vote.
Comments from GPs who took part were often negative about all political parties, with many suggesting they supported one party or another only as 'the best of bad bunch' or because they were deeply concerned about the alternatives.
One GP said: 'I am very conflicted and am finding it very difficult to trust any party to act in the NHS' best interests.' Another wrote: 'I have lost trust in any of the parties to look after my/our NHS. Any of them will say things that electorates like to hear. Who knows if they will really carry out their promises afterwards?'
In the week that the Conservatives promised 6,000 more GPs and 50m extra appointments a year, and Labour pledged a workforce boost to deliver 27m more appointments, GPs responding to the survey hit out at parties' election pledges. One accused the parties of 'too many cheap headlines and soundbites'.
A number of GPs planning to vote Conservative raised concerns about how the UK economy would perform under a Labour government. Others said they hoped a Boris Johnson government could offer the quickest route to moving on from Brexit.
Among GPs planning to vote Labour, many highlighted concerns that a Conservative government would lead to privatisation of the NHS - and said they were backing a Jeremy Corbyn-led government to bring an end to austerity and invest in and protect the health service.
Some GPs planning to vote either Labour or Conservative mentioned doing so despite concerns about the party's leaders - and among those planning to vote Liberal Democrat a distrust of either Mr Johnson or Mr Corbyn was mentioned by some as a reason why they had switched allegiances.
One GP planning to vote Liberal Democrat said: 'Both big parties are making outlandish claims. Worries me how far removed they are from reality.'
A GP who planned to switch to the Liberal Democrats said: 'I don't think Lib Dem will win so a wasted vote but can't see any alternative. Have voted Conservative previously but unhappy with Boris and recent Brexit nightmare.'
Several GPs planning to vote for the Liberal Democrats suggested hoping to avoid Brexit was their principal motivation - with others saying they had switched to the party to vote tactically against a local Conservative MP.
Several comments suggested that voting intentions were not fixed and that many GPs could change their minds between now and election day.
One GP responding to the poll said they were experiencing 'electile dysfunction: the inability to be aroused by any of the parties standing for an election'.