Opposition lawmakers this week called for a rally planned for the capital’s Freedom Park next week to be extended over three days as Cambodia National Rescue Party chief Sam Rainsy prepared to return from a much-vaunted overseas tour.

Tens of thousands of CNRP supporters are expected to take to Phnom Penh’s streets on Wednesday to deliver a petition to foreign governments demanding an investigation into irregularities in July’s elections.

Demonstration organisers wrote to Phnom Penh Municipality two days ago, informing the authorities that the CNRP would be extending the rally – which was originally due to last only one day – to October 25. But City Hall yesterday said it had not decided whether to authorise the protest.

Since it held a large rally in Freedom Park on October 6, the CNRP claims it has collected 1 million thumbprints for the petition.

“Our stance has remained the same, and the demonstrations will continue if our demands for justice are not met,” CNRP vice-president Kem Sokha said.

Cheam Yeap, a senior ruling Cambodian People’s Party lawmaker, again dismissed the opposition’s stance on the elections, saying the government had formed legally.

“The time [for protesting] has already passed,” he said.

According to the official count, the CPP won 68 of the 123 seats in the National Assembly while the CNRP won 55. The CPP maintains the vote was free and fair and has refused opposition demands for an independent investigation, although observers found serious flaws in electoral rolls and other irregularities.

CNRP leader Rainsy, meanwhile, met with US Deputy Secretary of State William Burns on Wednesday and was due to return to Cambodia yesterday after concluding his tour of Europe and the US.

Rainsy has threatened a general strike if the opposition’s demands are not met, a course of action that political analyst Peter Tan Keo cautioned against.

“A more effective approach would be for Mr Rainsy to find a moderate, as opposed to one that’s polarising, approach in negotiating a deal with the CPP,” he said in an email.

“While high-level State Department leaders and a few members of Congress will meet with the opposition … the US also is pragmatic in its relationship with Cambodia. They know that they have to work, and negotiate, with Mr Hun Sen, if they want to get business done.”

Jen Psaki, US Department of State spokeswoman, indicated in a briefing on Wednesday that the US was not about to take sides in the crisis.

“The United States continues to urge both parties to seek resolution of electoral disputes through a peaceful dialogue that serves the best interests of the Cambodian people and promotes reforms,” she said, adding that a “credible and transparent review” of the election was needed.

ADDITIONAL REPORTING BY DANIEL PYE