Mr Lansley (pictured) is expected to outline plans to fine hospitals when patients are readmitted as emergencies within 30 days of being discharged.
Under the plans, hospitals would get paid to support patients for up to a month to prevent them being discharged early.
Mr Lansley will be speaking at the Bromley by Bow Centre, in Bow, east London at lunchtime in his first speech since taking office as health secretary.
GPs will be hoping for more detail on Mr Lansley's key policy to hand commissioning responsibility to the profession.
BMA chairman Dr Hamish Meldrum, re-elected unopposed for a year on Tuesday, said: 'We understand the intentions behind these proposals and look forward to more detail. However, simply using financial disincentives is likely to result in unforeseen consequences.
'One risk is that we get a situation where decisions about discharge are based not on a judgement about what is best for the patient but on an attempt to avoid additional costs. This could result in patients being kept in hospital longer than necessary, when it might be better for them to be at home.
'The best outcomes are always likely to be achieved when primary and secondary care professionals are allowed to work together to achieve what is best for patients. We need models of healthcare that encourage co-operation rather than competition.'