Thousands of people across Scotland with routine appointments will be affected if the British Medical Association (BMA) announces on Wednesday its members have balloted for industrial action.
Around 81% of doctors said they were in favour of taking action in a recent poll.
Although full strike action was ruled out by the BMA in February, a work-to-rule could be imposed if doctors vote in favour of the action, resulting in major disruption to NHS services.
Doctors taking part in the dispute would attend their usual places of work, but all non-urgent and outpatient appointments that could safely be postponed could be cancelled over a 24-hour period. Thousands of GP practices will open only to deal with emergencies.
It is the first time since 1975 GPs have been balloted by their governing body, a move described as "a historic moment for doctors" by BMA chairman Dr Hamish Meldrum.
Dr Brian Keighley, chairman of the BMA in Scotland, has described proposals to increase the retirement age from 65 to 68, and increase pension contributions to 14.5% of salary for senior NHS staff within three years, as "totally unreasonable".
Doctors claim previous changes to the NHS pension scheme have already ensured it is "affordable and sustainable for the future".
The BMA Council is scheduled to hold a meeting on Wednesday to decide on the next steps. Ballot papers were sent to 103,000 doctors across the UK, from GPs and consultants to junior doctors, on Monday, May 14.
Members have been urged to answer "yes" to both questions for maximum legal protection if they want to take part in any industrial action.
The ballot papers polled members on whether they were prepared to take part in industrial action short of a strike, and whether they were prepared to take part in a strike. Some 30,000 public sector workers in Scotland went on strike earlier this month in opposition to the UK Government's proposed changes to their pensions.
The Coalition Government insists the Public Service Reform Bill, one of 19 measures announced in the Queen's Speech on May 9, will make public sector pensions affordable and sustainable.
A Department of Health (DoH) spokesman said: "Our proposals mean doctors will continue to receive pensions among the highest in the public or private sectors. A doctor joining the new scheme after 2015 could expect a pension of around £68,000 per year at state retirement age."
Scotland's Health Secretary Nicola Sturgeon has made it clear she will not take money from frontline services to cover a pensions shortfall. Ms Sturgeon has pledged to hold "open-minded" talks in a bid to find an alternative to the DoH plans.
Although the DoH proposals are intended to apply to NHS workers throughout the UK, Scotland has a devolved NHS pension scheme.
A Scottish Government spokeswoman said: "The Scottish Government is working within the restrictions imposed by Westminster to find a Scottish solution on pensions. We have urged doctors not to vote in favour of industrial action."