Jha said a conspiracy has been hatched by his political rivals to malign his image and he would retire from politics if found guilty.
"If Soni Devi can prove that I married her and fathered her child, I will resign from the ministership and retire from politics," Jha said.
"I am ready to undergo a DNA test to prove that her claims are false," he added.
Jha, however, accepted that he knew Soni as a BJP worker. But claimed her allegations were baseless.
"The birth certificate of her child shows Bhupen Chaudhary as the father. Even her voter ID, ration card and college register bears Bhupen's name as her husband," Jha said.
Soni Devi, a primary school teacher, had on August 18 alleged before the media in Dumka that she has been separated from her former husband since 1994 and had "married" Jha a few years later and has a four-year-old son from the "second marriage".
"I had been a BJP worker and know Satyanand Jha for last 20 years," Soni said.
Asked if she has any proof to prove her allegations against Jha, she said a DNA test would prove her claims.
She had in September last year also raised the issue before quickly retracting after the minister denied the allegations then.
