DETROIT  A possible merger of General Motors and Chrysler increasingly appears to hinge on federal aid, according to people with knowledge of the merger talks.

G.M. and Chrysler’s majority owner, Cerberus Capital Management, are said to be committed to a merger of the two troubled automakers but have yet to line up financing to inject more cash into the companies.

But investors are hesitant to put money into the deal without federal assistance in some form, possibly a direct loan or an equity stake, said people close to the talks who spoke on the condition that they not be named.

One person said Friday that G.M. was pursuing government assistance. A spokeswoman for the Treasury Department, however, said the rescue package was more focused on financial institutions.