The practice has been described as "sickening and immoral" by Michael Chong, head of the Malaysian Chinese Association (MCA) public service and complaints department, the Star newspaper said.
MCA is a political party and member of the ruling National Front coalition.
"It is a sickening practice and shames our nation. Women should be treated as equals and by no means are they to be paraded and sold in such a manner," Chong told the Star.
"This is definitely not showing respect to women."
He said the girls are sold for 20,000-30,000 ringgit each and are paid for on the spot and taken away by local men.
"The prettier and sexier the girl, the higher price she fetches," Chong said.
He said most of the girls are from poor families and hope for a better life by marrying Malaysian men -- mostly divorced, rich or old.
He said the authorities have no power to stop the unscrupulous agents as most of them had registered businesses.
"We cannot stop them from making money by selling foreign girls for marriages. But we can definitely stop them from parading the girls," Chong said, adding that he would inform the Vietnamese embassy in Malaysia if the parades continued.
"The Vietnamese authorities can then be on the look-out for the agents when they enter Vietnam to "recruit" more girls," he added.
"The practice of parading the girls and selling them off to local singles or divorced men mostly take place in rural areas that are highly populated with Vietnamese," he said.
Some of the small towns in Malaysia with large Vietnamese populations are in Triang and Jerantut in central Pahang state, he said.
He said that this way the prospective husbands are saved the "hassle" of traveling to Vietnam to see his future bride and then bring her back to Malaysia to register the marriage.