US President Barack Obama will not do anything that will discourage Malaysia from signing the Trans-Pacific Partnership Agreement (TPPA), said former prime minister Dr Mahathir Mohamad.

"I don't think he (Obama) will change anything. He wants (Prime Minister) Najib (Abdul Razak) to sign the TPPA.

"After that I don't know what will happen," Mahathir said at a press conference in Kuala Lumpur today.

Reuters previously reported that Obama would raise issues regarding the opposition in a meeting with Najib.

The Washington Post , however, reported that Obama is counting on Najib's administration to sign the TPPA.

Obama arrived in Kuala Lumpur today for his second trip in 18 months to Malaysia, this time to attend the Asean summit.

The TPPA is a multinational free trade agreement in which the US is a main proponent.

Apart from Malaysia, other countries involved in the just-concluded negotiations are Australia, New Zealand, Vietnam, Mexico, and Canada among others.

Parliament is expected to vote during a special Dewan Rakyat session early next year on whether to sign the TPPA.