Scores of demonstrators pushed down a gate to the parliament compound in the capital, Taipei, on Tuesday as police tried to prevent them from breaking into the building.
Retired General Wu Sz-huai fainted during the clashes while former Colonel Miao Te-sheng was seriously wounded after attempting to climb a wall and falling.
The protest came as the parliament was expected to discuss a bill targeting military pensions on Tuesday.
Another bill cutting civil servants’ generous pension packages had already been passed by lawmakers last June.
The protesters urged the government to revoke the bill passed last year and to hold talks over the new military pension plan.
“We have spent more than a year protesting on the streets. The Democratic Progressive Party (DPP) government has completely ignored us, our petitions, and protests,” a protester said in a video posted on the Facebook page of the protest’s organizers.
Vice President Chen Chien-jen announced the pension reform plan in January last year, including military pension cutbacks, triggering mass street protests.
The reform will be crucial for President Tsai Ing-wen, whose popularity has hit an all-time low since taking office in May 2016.
The presidential office urged the demonstrators to remain calm, saying the government had taken into consideration the veterans’ concerns in drafting the reforms.
“Military pension reforms are to ensure the pension system can develop sustainably,” it said in a statement. “Within the limits the state finance allows… we hope to offer the best solution.”
Slower economic growth and a rapidly aging population have forced the government to launch a quick shake-up in the pension system.