Patel was not specific in use of the term President's rule but he apparently meant the non-NDA governments would be destablised if Modi remains in power after the next general elections.
He stressed that all should unite to fight against the power which was trying to divide the country.
"I have clearly said that if the Narendra Modi government comes to power after the Lok Sabha elections in 2019 then it will invite President's rule in the country," Patel said while speaking to a local news channel here.
"All parties must come together to fight the power who are trying to divide the country," the Patidar activist said.
"I want to see someone as the Prime Minister of the country who will speak on education, employment, agriculture, health and security or safety of the country but not someone who spends 90 minutes criticising the opposition in the Parliament. I do not want such a Prime Minister," he said.
Heaping praise on West Bengal Chief Minister Mamata Banerjee for her "simplicity" despite being such a popular leader, Patel said he has learnt a lot during their last night meeting here.
"I have learned a lot from my meeting with Mamata di. I am amazed by her simplicity despite being the Chief Minister of a state. She has told me how to talk to the people and how to work taking everybody on board. She has advised me how one must have a little bit of attitude and how one should speak," he said.
Patel had met Banerjee at the state secretariat here last night and described the TMC supremo as "lady Mahatma".
"I saw lady Gandhi. She is a simple and selfless person. After Indira Gandhi, she has been the epitome of struggle for the cause of the people," he reiterated today.
Stating that Banerjee has invited him to join the TMC and manage its affairs in Gujarat, Patel had opined that the TMC supremo should lead the opposition.
Asked whether he would come to the state if Banerjee calls him again, the activist said "She (Mamata) has described me as her younger brother. And yes as I had said yesterday I will definitely come here to campaign during the Lok Sabha elections in 2019.