A political analyst has criticised the joint press conference between Dr Mahathir Mohamad and certain Pakatan Harapan and opposition leaders scheduled for tomorrow, describing it as a case of opportunism.

Speaking to Malaysiakini , Khoo Kay Peng said it is typical of Malaysian politicians to resort to such tactics.

"Clear-cut, it's opportunism," he said.

Opposition politicians, he said, are banking on using the "Mahathir platform" to do better in the next general election.

Khoo also believes the opposition is void of principles, especially since Mahathir has been clear in his objective – that his heart is still with Umno and he only wants to remove Prime Minister Najib Abdul Razak.

He said the opposition should cease talking about institutional reforms if they think Mahathir or taking down Najib is the solution.

"It works for Mahathir; it doesn't work for them," he said.

As such, he said the opposition could end up as losers but noted how both sides are of the opinion that they could score something out of this.

Lashing out at the opposition coalition, Khoo said it is disappointing that internal squabbles still occur despite its re-branding as Pakatan Harapan.

"In fact, they are even weaker than BN because they can't handle power.

"Give (them) a little bit of power, (they would) quarrel among themselves. That doesn't show to the people that they are able to handle power," he added.

Meanwhile, Penang Institute fellow Wong Chin Huat said it is not surprising that politicians are able to put aside their differences and work together.

He added that some are even of the opinion that it should have happened earlier.

"In my opinion, how far would they go is more important. Changing the ruler (Najib) is hardly anything long-term. Changing the rules (institutions) would do," he said.

Earlier, PKR vice-president Nurul Izzah Anwar revealed that Pakatan Harapan would hold a press conference with Mahathir tomorrow.

It was later clarified that she meant individual leaders and not the coalition itself.

This was in response to a question on Mahathir's proposal to set up a core group against the leadership of Najib.