We report the rovibronic line oscillator strengths of N2 in the 83.4 nm region at high temperatures measured by using ultrahigh-resolution photoabsorption spectroscopy. The measurements have been carried out using a resolution of 6.5 ¿ 10-4 nm and at temperatures of 600, 535, and 295 K. The N2 absorption features in the 83.4 nm region mainly involve the (0,0) band of the c'6-X transition and the weaker (2,0) band of the c4-X and the (25,0) band of the b'--X transitions. Spectral perturbation effects in the c'6-X transition have been observed at J (rotational quantum number) >14. The presence of weak transitions and hot band transitions further contribute to the spectral complexity, especially in the long wavelength side. By integrating over each individual absorption profile for each rotational line up to J = 16, the rovibronic line oscillator strengths of the (0,0) c'6-X transition of N2 are measured. For the spectral regions with strong perturbations and overlapping by the weak (2,0) c4-X and the (25,0) b'--X transitions, we have measured the effective oscillator strength values with a roughly equal spectral step covering the perturbed features in the 83.422--83.477 nm region. The present results will contribute to a correct interpretation of the OII 83.4 nm EUV airglow emission of the Earth by elucidating the effect of temperature on the atmospheric extinction due to absorption by N2 and O2.