"He was a secular in true sense and had contributed for the development of Bihar," Kidwai said in his condolence message.
Singh (83), a former Bihar minister, died of age related illness at a private hospital here on Saturday last.
In a separate condolence message, former Bihar minister Shamaele Nabi said minorities and poor have lost their true sympathiser.
"Lifelong Singh had worked for the marginalised sections of the society," he said.