MANJUNG (THE STAR/ASIA NEWS NETWORK) - Umno deputy president Muhyiddin Yassin is not the party leader who is trying to topple the Prime Minister Najib Razak, said Malaysian Deputy Prime Minister Ahmad Zahid Hamidi.

Datuk Seri Ahmad Zahid said party members should not blame Tan Sri Muhyiddin as he was not involved.

Declining to name the "orang tua" (old man) who wants to oust Datuk Seri Najib, Dr Ahmad Zahid said the alleged "plotter" wants to form a unity government with the opposition.

"He is someone who has a big ambition. He is trying to enter through the 'backdoor'.

"Personally, me and Datuk Seri Zambry Abdul Kadir are close to Tan Sri (Muhyiddin).

"We respect him as the deputy president. We will not pijak (step on) those that have fallen," Dr Ahmad Zahid said during the opening of the Lumut Umno annual general meeting on Sunday.

He also said he would not allow anyone to form a unity government through the "backdoor".

Dr Ahmad Zahid had said earlier that the alleged "plotter" would meet the Prime Minister at 6pm on Sunday.

However, there was no sign of any alleged "plotter" meeting with Mr Najib at either his official residence in Putrajaya, nor his personal residence here, after media representatives had camped out at both residences.

Reporters and photographers left at about 9pm on Sunday without seeing anyone going in.

Mr Najib arrived at his house in Jalan Duta at about 7.50pm from Gerik where he had earlier opened the Gerik Umno division meeting.

A black car with a lone woman in dark suit sitting at the back arrived at Mr Najib's house at about 8pm.

The driver paused for a few minutes in front of the house, but decided to drive further up the road and waited metres away from the main entrance before driving off about 10 minutes later.

Both former Mr Muhyiddin and Gua Musang MP Tengku Razaleigh Hamzah have denied being part of any conspiracy to topple the Government.

Umno vice-president Shafie Apdal said a thorough investigation must be carried out to determine if a senior Umno figure was the mastermind of a plot to topple the government.

The truth behind the allegations must be brought to light and the wrongdoers should be punished, he added.

"That is why a thorough probe must be carried out to find out the facts behind these claims. Something as significant as this must not be allowed to fester," he said late on Sunday.

"In a democratic system, there are laws and regulations which must be upheld. If any Umno member is found to have to have contravened any law, then appropriate action must be taken against that person," Datuk Seri Shafie added.

Veteran politician Rafidah Aziz has described the allegation of a plot to topple the government from within Umno as "shocking".

The veteran politician said there is no gain for anyone, especially within the party, to make such a move.

"Isn't that like cutting off your nose just because you hate the face?" the former international trade and industry minister wrote in a post on her Facebook page, Monday.

She said it was people who determined the future of leaders, and not those who engaged in conspiracy.

Tan Sri Rafidah reminded Umno and Barisan Nasional to focus on serving the people instead of looking at short-term fixes.

"We are still saddled by issues such as 1MDB and the RM2.6 billion political donation. We are going through uncertain economic times due to investors' loss of confidence.

"We are still bogged down by parochialism, narrow perception and holding the ideals of ultras in various fields which can split us.

"In short, the leaders should fully concentrate on governing the country and solving problems. There''s no point for anyone especially those in Umno and BN to bring down the leader and the government," she said.

Tan Sri Rafidah went on to remind those who are focused on bringing down certain individuals not to get too carried away.

"The party members are watching our action that is being portrayed to them and certain quarters will exploit those actions.

"The people who have the power to vote are watching our political games and acts and will decide our fate when the time comes," she said.

Inspector-General of Police Tan Sri Khalid Abu Bakar confirmed Monday that the allegations are being investigated.