Catalyzes phosphite (phosphonate) oxidation. H2O + NAD(+) + phosphonate = H(+) + NADH + phosphate Inhibited by NaCl, NADH and sulfite. Optimum pH is 7.25-7.75. Optimum temperature is 35 degrees Celsius. Homodimer. By phosphate starvation. Belongs to the D-isomer specific 2-hydroxyacid dehydrogenase family.