Investigations will continue on Tan Sri Muhyiddin Yassin for making a speech outside of the UMNO General Assembly 2015, Datuk Seri Hishammuddin Hussein said.

The UMNO vice-president said this was in spite of the UMNO deputy president apologising for his actions, if he apologises, that is.

"The investigation must continue. If it (Muhyiddin's action) is wrong, then it's wrong. It has got nothing to do with him making an apology, if he apologises," Hishammuddin told newsmen at an UMNO vice-president media conference at the Putra World Trade Centre today.

Last Monday, Muhyiddin, who is former deputy prime minister, had addressed a gathering held at the Kelab Sultan Sulaiman in Kampung Baru in the federal capital.

His act had been heavily criticised by several quarters, including UMNO secretary-general Datuk Seri Tengku Adnan Tengku Mansor, who deemed Muhyiddin as 'crossing the line' and could lose his party position because of it.

Meanwhile, when asked on the absence of another UMNO vice-president, Datuk Seri Shafie Apdal at the media conference today, Hishammuddin replied: "The chair next to Datuk Seri Zahid is still being filled on stage, so we have no problem. Being present onstage is way more important than being at this Press conference."

Hishammuddin, who is also Defence Minister, said the matter of UMNO making room for forgiveness for Shafie was never an issue as the party is always open.

"The vice-president is wearing red, the same as us on the first day and I didn't sense any awkwardness at all, as how the media had predicted before this," he added.