The Bharatiya Janata Party leader said the Left parties wanted a split mandate so that they could put together a Third Front.
He also indicated that the Congress' regional rivals would automatically ally with the BJP-led National Democratic Alliance (NDA).
"Rahul Gandhi has categorically said that his party would not support the Third Front," Jaitley said in a blog on Sunday.
"The Left hopes for an indecisive mandate. Their best case scenario is that in a situation everybody else gangs up to keep the NDA out. Will this include TMC and the Left being on the same side or the BSP and SP, the DMK and the AIADMK to come up on the same side?" the BJP leader asked.
"Those who occupy the non-Congress space in their states will find it impossible to side with the Congress in Delhi. If they did side with the Congress in Delhi, they will end up conceding their non-Congress space to the BJP."
While stating that the BJP-led NDA was heading for a "comfortable majority" in the Lok Sabha, Jaitley said: "The best case scenario for the Congress is a rag tag coalition to keep Modi out.
"The choice now is clear. It is either a Modi-led NDA or a chaotic coalition."