Hu Yu-wei, who is also the information minister, Sunday posted a picture of the latest Apple smartphone and a line reading "Bolster consumption and economy", sparking a wave of criticism.
In the face of mounting pressure, Hu later posted on his Facebook page another picture of an HTC cellphone which he said is the one he uses himself. The iPhone 5 he originally posted belonged to a friend, he said.
"As a government official, Hu should have done whatever he could to promote the domestic economy at a time when it is in trouble," the United Daily News said in an article Monday.
The row highlighted the difficulties facing HTC, Taiwan's leading smartphone maker, amid intense competition from Apple and Samsung.
HTC's net profit in the three months to June plunged 58 percent from a year earlier due to slowing global demand.
Net profit in the second quarter was Tw$7.4 billion ($247 million), compared with Tw$17.52 billion a year earlier but up from Tw$4.46 billion in the 2012 first quarter.
Exports by trade-reliant Taiwan posted a year-on-year decline of 11.6 percent in July due to shrinking overseas demand for information technology and telecom products.