Former Umno secretary-general Mohd Radzi Sheikh Ahmad has warned his party not to underestimate Dr Mahathir Mohamad and former deputy prime minister Muhyiddin Yassin.

Mohd Radzi in an interview with Oriental Daily, said Umno today faced a challenge greater than that posed by splinter party Semangat 46 in the late 1980s.

At the time, he said, Umno's main detractor was Tengku Razaleigh Hamzah alone. Now the party has numerous former senior party leaders as opponents.

"The party led by Mahathir will only contest in Umno seats. This is a big challenge for Umno."

He predicted that should Umno and PAS work together ahead of the next general election, they would likely be defeate at the hands of the Pakatan Harapan-Bersatu alliance.

Mohd Radzi is a veteran Umno politician who had served as Kangar MP for several terms. In cabinet, his highest position was home minister.

On the 1MDB controversy, Mohd Radzi warned that the matter will take at least "one generation" to forget and that it had left a deep mark on the Malaysian political landscape and international image.

"You can say the rural folks don't care about the 1MDB issue, but the debt will be paid by the next generation.

"They may not know about 1MDB, but the rising cost of living will affect their livelihood, because 1MDB had led to this," said Mohd Radzi.

He said the youth of today know about the 1MDB issue and no amount of explaining by the government would sway them.

Red shirts damaging Umno's image

Mohd Radzi also claimed the red-shirts movement was not beneficial to Umno's public image.

He said that Malay youth were turned off by their antics.

"If Malays feel this way, what about other ethnic groups? I am very sad (because) Umno is affected by this negative image," he said.

He said that Umno was once respected by all ethnic groups because the party was just and looked out for all.

"Causing a ruckus is not work. Do you think putting on a red shirt is enough to win over voters? We need to win their trust, then they will vote for us.

"Will wearing a red shirt make you a hero?" he asked.

On the likelihood of Umno cooperating with PAS, Mohd Radzi said this was improbable because of the history between the two parties.

Mohd Radzi said Umno members will not forget that PAS president Abdul Hadi Awang had once decreed that Umno was a "kafir (infidel)" party.

"There are still Umno members who can't forgive Abdul Hadi," he said.

Moreover, Umno and PAS traditionally contest against each other and to cooperate means having to share seats.

"Is it that easy to achieve this? Not at all. PAS won't give way an inch," he said.