The assembly's planning and housing committee has launched an examination of how planning can be used to prevent smaller retailers from closing. The study will look at examples of good practice as well as the merits of new legislation.
A clampdown on changes of use and the scope for primary legislation will also be considered. The final report will feed into consultation on the London Plan.
Chairwoman Jenny Jones said: "We will look at existing planning guidelines to ensure that we are putting them to best use. But we may also come up with ideas that require primary legislation. If we want to protect small shops we need to think about how we counterbalance the effect of big business."
Knight Frank planning partner Jonathan Drew warned: "Trying to deal with this with national or regional guidance is fine as long as it is a framework rather than too prescriptive. A legislative approach may not pick up local sensitivities."