Thailand's opposition leader has urged that a general election planned for July be delayed to allow time for reforms aimed at ending a protracted political crisis that threatens to explode.

Protesters have been trying to oust Prime Minister Yingluck Shinawatra since November.

It is part of a long-running crisis that broadly pits Bangkok's middle class and royalist establishment against the mainly poor, rural supporters of Ms Yingluck and her brother, ex-premier Thaksin Shinawatra.

Mr Thaksin was ousted by the military in 2006 and now lives in exile to avoid a jail term handed down in 2008 for abuse of power.

His opponents accuse him of corruption and nepotism.

Thailand's Election Commission and Ms Yingluck agreed on Wednesday to hold a general election on 20 July.

However, anti-government protesters who disrupted a vote in February said they still wanted electoral reforms before a new poll.

Former prime minister Abhisit Vejjajiva, who launched a mediation effort on 24 April, told a news conference the vote should be delayed by five or six months while a committee thrashed out reforms that would be put to a referendum.

While that was being done, he wanted the country to be run by a neutral interim government with limited powers.

The panel should include representatives of the People's Democratic Reform Committee (PDRC), the protest group led by Suthep Thaugsuban, who was a deputy prime minister under Mr Abhisit until 2011.

Mr Abhisit said: "I have said from the start that no side will get what they want 100% from what I am proposing.

"But ... the government will see an election, people will get to vote in the next five to six months.

"The PDRC protesters will get their neutral government,"  he said.

He said he would not be part of the reform committee and that no politician should sit on it, but he gave few details on its likely composition.

He also said he would not take up a political position in future if his plan was accepted, although his medium-term intentions are unclear.

"I would like to ask Yingluck: is there any part of my proposal that damages the country?" he said.

There was no immediate comment from Ms Yingluck on his plan.

But Jarupong Ruangsuwan, leader of the ruling Puea Thai Party, told Reuters that the government could not accept Mr Abhisit's proposal and that the cabinet will deliberate a draft royal decree for the 20 July election date on Tuesday.

"The government cannot accept Abhisit's plan because it is outside the framework of the constitution. Abhisit's plan will only increase divisions in Thai society," Mr Jarupong said.

"Asking the government to resign is tantamount to ripping up the constitution. We will push ahead with preparing the draft (election) decree."