The health and social care secretary told MPs on the House of Commons health select committee that he could set a new deadline as part of the final NHS People Plan.
He admitted that the 2020 deadline for adding 5,000 GPs to the workforce set by his predecessor Jeremy Hunt had slipped because 'there wasn't enough focus on retention'.
Responding to the comments, BMA GP committee chair Dr Richard Vautrey told GPonline that although a new deadline may 'focus minds', it was no substitute for 'fundamental steps to address recruitment and retention' in general practice.
An interim people plan published in June promised incentive schemes to boost the GP workforce. The final version, which will aim to tackle 'once in a generation workforce challenges' faced by the NHS, is expected to emerge after the government's next spending review - potentially later this year.
Mr Hunt promised to add 5,000 FTE GPs to the NHS workforce by April 2020 from the September 2015 baseline. But Mr Hancock dropped the deadline last year, admitting that increasing the GP workforce had 'proven difficult to say the least'.
Health select committee member Andrew Selous, Conservative MP for South West Bedfordshire, asked Mr Hancock to explain 'what you have learned from the failure of the 2016 GP Forward View to get the extra 5,000 GPs in place by 2020'.
He questioned the government's current position that it will deliver the extra GPs 'as soon as possible', and called for a new deadline.
NHS People Plan
Mr Hancock said: 'Why don't I look and see if I put a date on it in the final People Plan.' He added that when he became health and social care secretary 'I arrived to find we were missing the target, in fact going backwards'.
But he said: 'I was very clear we needed to keep the target and work on a date it was realistic to hit it by. I will go away and work on that.'
Asked to explain why the government had been unable to deliver 5,000 extra GPs, he told the committee that the 'number one focus' in recent years had been on hiring new GPs - pointing out that with record numbers of GPs in training, this had 'been successful'.
But he admitted: 'I think there wasn't enough focus on retention, both in terms of people doing full-time work and in terms of keeping people in NHS general practice. The people plan focuses on new staff and retention.'
The health and social care secretary said that GP numbers were now 'going in the right direction'. Between September 2015 and March 2019 - the most recent figures available from NHS Digital - the total number of FTE GPs has risen from 34,262 to 34,736.
However, the number of fully-qualified GPs in permanent roles - excluding locums and trainees - has dropped by more than 1,200 over this period, from 28,631 to 27,381.
Mr Hancock said that tackling early retirement was 'partly about incentives' - highlighting the need to address pension taxes that have pushed many GPs to retire early or work fewer hours. But he said it was also 'about workload' - and that the NHS was moving to a system with 'far more support from other health professionals around GPs'.
Dr Vautrey said: 'We need to see fundamental steps to address recruitment and retention in general practice. Deadlines can help focus minds, but we need a real package of proposals to inspire confidence.
'We have said that the new contract and PCNs are part of the solution, but they won't solve problems created over the past decade or more alone.'