Longer appointments were identified by 54% of GPs as a key factor that could help them diagnose blood cancer - which has non-specific symptoms that can be tough to identify in a standard 10-minute consultation, the poll by charity Bloodwise found.
The finding comes less than a year after the RCGP warned in a document setting out its vision for the future of general practice that 15-minute appointments would be the bare minimum a decade from now.
Other changes that could improve detection rates flagged up by GPs included better CPD training (48%), better access to summaries of NICE guidance (35%) and better training in medical schools (33%). Other GPs called for improved access to phlebotomy services and better relationships with hospital specialists.
Analysis of the NHS National Cancer Patient Experience Survey by Bloodwise shows that around one in three patients with blood cancer visit their GP three or more times before the disease is diagnosed - while other cancers are picked up more quickly.
Dr Sam Merriel, a GP and academic at the University of Exeter Medical School said: 'This survey highlights the barriers we face in diagnosing blood cancer. It often presents with non-specific symptoms making it difficult to identify, especially when the time we can spend with the patient is so limited.
'GPs need training and educational resources - from medical school right through to continuing medical education for established GPs. The curriculum for GPs is very broad and, at just three years, we have the shortest speciality training programme. The RCGP position is that we should have a longer training programme, but that has not materialised yet.'
Bloodwise policy manager Phil Reynolds said: 'Delays in treating cancer cost lives and a higher proportion of people with blood cancer are diagnosed late in comparison to any other common cancer. If the government is to make good on its promise that the NHS will diagnose cancer faster, GPs must be given the information and support they need to identify patients with blood cancer.
'Plans to recruit new GPs are a step in the right direction if it will result in longer consultations with patients. However, as this survey shows, there is a clear need for training to help GPs identify possible cases, know how to interpret often-complex test results and when to use safety-netting for patients with unexplained symptoms.
The charity has set up a petition calling on the government to improve support for GPs to pick up blood cancer and produced a guide to help patients and GPs.
Symptoms of blood cancer include unexplained bruising or bleeding, unexplained weight loss, lumps or swellings, tiredness, persistent infections, rashes, bone or joint pain and drenching night sweats.