Kishor, who joined the JD(U) in September last year, made the comments in response to queries about his recent visit to Mumbai, where he met Shiv Sena chief Uddhav Thackeray, fuelling speculations about a strategic alliance between his party and the Maharashtra-based outfit, which, of late, has been critical of Modi's leadership.
A resident of Buxar district in the state, Kishor shot to fame in 2014 when he managed the poll campaign for Narendra Modi, then the prime ministerial candidate of the BJP, which went on to put up its best-ever electoral performance.
A year later, he collaborated with Kumar who returned to power for his third consecutive term after registering a handsome victory in the assembly polls.
"I met the Shiv Sena chief upon his invitation. The party is an NDA constituent and so there is nothing out of place in both of us (Thackeray and Kishor) having discussions. The speculations of my helping them with poll strategy do not have any substance. I am now a member of a party and cannot offer such professional assistance," he told reporters.
Asked about the chances of Nitish Kumar becoming the prime minister and he the deputy PM, in the event of the BJP falling short of adequate numbers, Kishor said, "No discussion of the sort took place. Kumar is a big leader. Anybody who has ruled a major state like Bihar for close to 15 years is bound to have a stature. But it would be unfair to him if we start considering him a claimant for the prime minister's post."
"Narendra Modi is the NDA's prime ministerial candidate and he will return as the Prime Minister again. Nitish Kumar will have a role to play, of course. Among NDA constituents, the JD(U) is the third largest after the BJP and the Shiv Sena. But nothing more should be read into this," he added.
Kishor also said that during his meeting with Thackeray, whose party has often been accused of spreading hatred against the people from Bihar, "the issue of the safety of Biharis living in Maharashtra was taken up. I said that in Bihar, the JD(U) would ensure the well-being of Maharashtrians and expressed hope that his party would respond in kind."
To a query about allegations levelled by opposition parties that law and order had deteriorated in Bihar in the recent times, bringing disrepute to the Nitish Kumar government, Kishor said, "Statistics speak otherwise."
"People often say it is the first term of Kumar, from 2005-2010, when the law and order situation was the best. Perhaps it was because people experienced a welcome change from the days when Bihar, comprising only 10 per cent of the country's total population, witnessed more than 20 per cent of incidents of robberies and other crimes."
"Statistics say that the law and order situation today is even better than what it was during Kumar's first tenure. But with people getting used to peace and order, expectations soar and this is not something we can complain about, but must gear up and face as a challenge," he added.