A loyalist of jailed leader Najib Razak has urged Umno to limit its cooperation with DAP, saying anything more than an alliance in the federal government would only make it difficult for the Malay party to emerge from its current political decline.

Isham Jalil, a member of the Umno Supreme Council, said the party was in dire need of regaining the trust of grassroots members following its move to strike an alliance with Prime Minister Anwar Ibrahim's Pakatan Harapan (PH) coalition.

Isham, who said that the outcome of the recent by-elections in Pulai and Simpang Jeram was a sign that the party would be wiped out in the next general election, also warned that no party can survive without support from its grassroots members.

"If a party loses its grassroots support, it becomes irrelevant, and it's like a reluctant life that refuses to die. We cannot be in this state.

"We need to restore our grassroots support and their trust in us, not by forcing them, let alone asking them to deviate from the fundamental struggle," said Isham, who was sacked as the Selangor information chief before being appointed by Umno president Ahmad Zahid Hamidi to the party's Supreme Council last year.

On Sept 10, Zahid and several Umno leaders became the first delegation from the party to attend DAP's annual conference.

The event was held a day after PH won the two by-elections with help from Umno leaders, securing the seats for another term amid a widespread transfer of Malay support towards Perikatan Nasional (PN).

PH retained the Pulai and Simpang Jeram seats, albeit with reduced margins of support. Zahid, the Barisan Nasional chairman, said in the run-up to the polls that his coalition was taking "proactive steps" to ensure a transfer of support for the PH candidates.

Isham said it did not make sense for Umno to claim it was championing the Malays while working with DAP.

"The rhetorical agreement that DAP won't touch the rights of the Malays is meaningless when they've openly said that they'll continue with the 'Malaysian Malaysia' concept.

"One day, when they're in power and have more seats, and we rely on their votes, I wouldn't be surprised if they implement their 'Malaysian Malaysia' agenda. This is a significant detriment to the Malays," Isham, Najib's former special officer, added.

"Only when it has already happened will we realise our mistake. When it happens, it'll be too late."

Isham also said that cooperation with DAP should stop at maintaining the federal government, adding that this was how Umno joined hands with PN in the past without forming an electoral pact.