Plea of innocence
"If they seek to use the case to cause me trouble or even knock me down, they won't reach their goal"
Ma Ying-jeou, presidential frontrunner
The 56-year-old told the court that his use of the discretionary funds without providing detailed accounting was an approved government practice for over 20 years.
Ma is the favourite to take over from Chen Shui-bian as president in elections on March 28.
On Sunday, he said his campaign would proceed even if he were convicted.
"If they seek to use the case to cause me trouble or even knock me down, they won't reach their goal," he said.
On Monday, Wang Jin-pyng, a Nationalist party leader, announced he would not contest the party's presidential primary due to an alleged bias in the process, fuelling rumours of a possible independent bid for Taiwan's presidency.
"The primary would never be a fair competition as the rules of the game were specially made for a particular candidate from the outset," Wang said.
Both the Nationalists and Chen's Democratic Progressive party (DPP) are expected to announce their presidential candidates in May.
Chen is constitutionally barred from a re-election after serving two four-year terms.