Social and Family Development Minister Tan Chuan-Jin said Workers' Party (WP) MP Png Eng Huat was "stirring hate and anger" when he questioned why Mr Tan and a group of grassroots members with him were given expedited clearance at the Tuas checkpoint on Sunday evening.
Hougang MP Png had said on his Facebook page on Monday that he and his residents, who had travelled to Johor for durians, had to wait in line "for hours" but saw Mr Tan and some of those with him being allowed to use a counter specially opened for them.
"One of my residents is 89 years old and another was injured during the tour. If these two elderly residents can wait in the queue patiently...so can all my volunteers and grassroots members," wrote Mr Png.
After the Immigration and Checkpoints Authority (ICA) made it clear that it was normal practice for both Malaysian and Singaporean ministers to be given expedited clearance, Mr Tan, who is an MP in the Marine Parade GRC, posted on his Facebook page that Mr Png was trying to "politicise the issue".
He said the post was "aimed at stirring hate and anger, not only to be directed at me, which I can understand politically, but also at my residents and volunteers, as well as our officers who secure our borders".
Mr Tan said he had travelled to Johor for a durian trip with his residents, as well as making an official visit to a Hari Raya open house held by Malaysian Deputy Home Affairs Minister Nur Jazlan Mohamed.
"On the return journey, ICA facilitated the clearance for me and my security officers who were carrying their firearms, as well as the residents and volunteers who were with me on my bus," he added.
ICA said that besides the bus carrying Mr Tan, the other 19 buses ferrying his group queued up and were cleared through normal channels.
Mr Tan said: "Mr Png seems to accept that it's reasonable that our office holders get facilitated; if so, then surely the others in that bus need to be cleared as well so that the bus can leave and not add to the vehicular queues there."
He pointed out that Mr Png had given the impression that his wait to clear immigration was long, when it was half an hour.
Mr Tan pointed out too that he had also bumped into Nee Soon MP Louis Ng and his group at the checkpoint, and that he, like Mr Png, also had to wait in line.
As for the injured and elderly residents with Mr Png, Mr Tan said: "Any traveller who requires special assistance can approach our ICA officers on duty."
When contacted, Mr Png said that the issue was not about Mr Tan, but that those travelling with him were given expedited clearance - a point he stressed again in a later Facebook post.
"The expedited clearance for (Mr Tan) comes with the position he is holding and for security reasons. My volunteers worked very hard too. I don't have an issue with Minister Tan, personally or politically. I have an issue with inequality."