Another day of action could see doctors running a Christmas Day-style service, with only emergency services operating.
At the British Medical Association (BMA) conference in Bournemouth, a large majority of delegates voted on a motion which said "further industrial action was necessary".
Doctors also called on UK Health Secretary Andrew Lansley to resign, saying they had no confidence in him. But they stepped back from demanding another day of action be called immediately.
Last week doctors took industrial action for the first time in almost four decades by boycotting non-urgent care.
The BMA announced the move after it accused ministers of pressing ahead with "totally unjustified" increases in pension contributions and a later retirement age for doctors.
Yesterday, doctors proposed further action by the BMA should be co-ordinated with other unions to maximise its impact. They urged BMA leaders to "consider a range of options in defence of our pensions" including "withdrawal from clinical commissioning activity" and "in secondary care, withdrawal of labour with emergency cover only".
Even though the motions were passed by delegates, under BMA rules only the body's full council can authorise such action.
Proposing the motions, Dr Kevin O'Kane said: "If we want to protect our pensions, we need to stay united and have no choice but to take further industrial action.
"Andrew Lansley, you've driven doctors to take industrial action for the first time in 40 years, well done. We don't want to take this action, it doesn't come naturally to us, but be assured we are fast learners."
The action last week left thousands of patients unable to have a planned operation or see their specialist or GP. Figures show the action last Thursday hit almost one-fifth of GP practices.
Dr Brian Keighley, chairman of the British Medical Association's Scottish Council, warned this week that Scots doctors will take part in more strike action unless the Scottish Government shows it is committed to overruling Westminster-driven changes to pensions.
The GP said the SNP could use money from Scotland's block grant from Westminster to cover the doctors' increased pension contributions and keep their retirement age at 60, which would mean they would not need to work a further eight years.
He said: "I would ask the Government to throw us some sort of concession to show they are willing to take another approach. The amount this would cost would be very limited."
The Scottish Government runs the pension scheme north of the border. Health Secretary Nicola Sturgeon previously said she regrets the action but the Scottish Parliament has "limited room for manoeuvre".