He said Gabungan Parti Sarawak (GPS), the ruling coalition, had been given such an assurance during a meeting with leaders of PPBM last year.

“We were assured that PPBM will not participate in any election in Sarawak, so we expect them to keep their word.

“A promise is a promise. No one should break a promise to serve their political convenience. If PPBM reneges on its promise, then we have no choice,” he added, hinting GPS would go against PPBM to defend Sarawak’s rights and interests.

“When it comes to the interest of Sarawak, it is non-negotiable.”

GPS was formed by PRS, Parti Pesaka Bumiputera Bersatu, Sarawak United People’s Party and Progressive Democratic Party in May 2018, after the four local parties quit Barisan Nasional (BN) in the aftermath of the last general election (GE14), when BN lost Putrajaya.

The four parties decided to stand on their own and fight for autonomy rights listed under the Malaysia Agreement 1963.

Masing, who is also deputy chief minister, said even Umno had kept its promise not to contest in Sarawak despite its strength in earlier days.

He was commenting on Umno veteran Shahrir Abdul Samad’s social media posting that Umno would not contest in the Sarawak state elections as the party respected its former partners in BN, who are now in the GPS coalition.

“It is not about seat (allocation) but out of respect,” he wrote.

In the posting, Shahrir said: “We will wait (and see if PPBM will contest in Sarawak) as they had already set foot in Sarawak when they accepted two MPs from the state.”

He was referring to Puncak Borneo MP Willie Mongin and Saratok MP Ali Biju, who quit PKR and joined PPBM. Another MP in Sarawak, Julau’s Larry Sng, also quit PKR last month to become an independent supporter of the Perikatan Nasional-led government.

PPBM, Shahrir said, had also promised not to spread its wings to Sabah prior to GE14.

“But, in the end, they also contested in the Sabah state polls and even hold the chief minister’s post now,” he said.