His comments came amid speculation that the Obama team might announce plans to create within days of coming to office an “aggregator bank” to take on the toxic assets clogging up the system.
Mr Summers told CBS' Face the Nation that the $825bn fiscal stimulus now before Congress was only “one phase” of Mr Obama's economic programme and would be accompanied by a financial reconstruction plan and new housing policies.
He said the fiscal stimulus would start to have an impact on the economy “almost immediately”, as households anticipated higher income and transfers to state and local governments prevented them from having to lay off public sector workers.
The incoming NEC chief said bank capital injections would come with greater conditionality. Banks “would be expected to use that money productively”, he said.
Mr Summers did not offer any specific comment on the mooted “aggregator bank”. The Obama economic team has discussed the possible creation of such a vehicle with officials.