Lobby group Right2Know (R2K) has questioned whether State Security Minister David Mahlobo can be trusted.

This follows contradictory statements he made this week on his relationship with Wits student leader Mcebo Dlamini.

On Monday, Mahlobo told a public seminar that he knew Dlamini and the student leader had been to his house several times.

But on Wednesday, he made an about-turn and said the meeting never took place and Dlamini had never been to his house.

"One of those statements is untrue: The question is if he misled a public seminar or misled Parliament itself. If he misled us on this issue, when can the minister’s words be trusted?” R2K said in a statement on Friday.

Mahlobo was in the spotlight this week following allegations that he was a frequent visitor to a well-known self-confessed criminal Guan Jiang Guang’s massage parlour.

R2K said it was long past time for Mahlobo to go.

"This week David Mahlobo showed conclusively that his words cannot be trusted. Whatever role he may have had in building a safer and more democratic South Africa is now impossible. In the last two years, Mahlobo has presided over a dangerous creep of state security into our politics and public life."