GP services are in "crisis", leading doctors are expected to say.
The current workload family doctors are facing is "unsafe and unsustainable", delegates at the British Medical Association's (BMA) annual meeting in Bournemouth are to argue.
Doctors are to call for a "rapid expansion" of the GP workforce to help deal with the pressure.
Pledges have already been made to increase funding, but medics are to say they need more money "as a matter of urgency".
Meanwhile, one of the motions to be debated at the conference is a call for GPs to be able to issue so-called black alerts to show they have reached maximum safe capacity.
The motion, tabled by the East Midlands Council arm of the union, says: "This meeting notes the regular declarations of 'black alert' by hospitals and demands that a similar reporting system be created for general practice to indicate that maximum safe capacity has been reached."
Black alerts are issued at some hospitals when they reach capacity, usually meaning they will divert patients elsewhere for emergency care.
Meanwhile, Dr Chaand Nagpaul will make his final speech as chairman of the union's general practice committee before taking on the top BMA job.
He will become chairman of BMA council after Dr Mark Porter stands down on Thursday.
On Tuesday, medics at the conference backed a motion calling for the decriminalisation of abortion.