KUALA LUMPUR (Reuters) - Malaysian opposition leader Anwar Ibrahim vowed on Tuesday to lead a "fierce movement" to reform the country's electoral system and challenge the results of an election he lost, starting with a rally of supporters this week.
Anwar has contested the results of the most closely fought election since Malaysia was engulfed in race riots in 1969, accusing the ruling party of fraud, including use of immigrants as proxy voters, charges the government denies.
He has called for a mass rally outside the capital on Wednesday.
But his mobilisation of supporters, echoing the "reformasi" movement he led 15 years ago, is unlikely to prevent Prime Minister Najib Razak's Barisan Nasional (BN) from extending its unbroken run as Malaysia's government following independence from Britain in 1957.
By Tuesday afternoon, about 20,000 people had confirmed on a Facebook page that they would attend the rally. But the gathering is not backed by the Bersih (clean) civil society group that has mobilised tens of thousands of people in protests that have shaken the government in recent years.
The rally, which Anwar emphasised was not a protest, is to take place in a stadium with a capacity of about 40,000 in Selangor state near Kuala Lumpur, retained by the opposition in state elections held alongside the national poll.
The rally "will be the beginning of a fierce movement to clean this country from election malpractices and fraud", the 65-year-old former finance minister told a news conference.
Anwar said the opposition had ample evidence to challenge the election result in up to 29 seats, enough to call into question the overall national result.
The government rejected the opposition's claims, saying the result which returned Najib to power with about 57 percent of the seats in parliament was in line with opinion polls in recent weeks. Najib's BN, however, won only 47 percent of the popular vote, compared with the opposition's 50 percent.
"The opposition has made a host of unsubstantiated allegations about the elections," a government spokesman said.
The country's Election Commission, which is a unit of the prime minister's office and has been criticised by the opposition and civil society groups as biased, is unlikely to investigate Anwar's charges.
The opposition alliance won 89 seats in parliament compared to the BN's 133, despite the ruling coalition receiving a minority of votes nationally for the first time in 44 years.
Bersih has said it will hold a "peoples' tribunal" to investigate evidence of fraud before deciding whether to hold another major protest.
The rally offers a reminder of Anwar's past efforts to challenge one of the world's longest-surviving governments after his meteoric career came crashing down in 1998 when he fell out with the then-prime minister, Mahathir Mohamad, his mentor and Malaysia's longest-serving leader.
He was sacked as deputy prime minister and imprisoned on what he says were politically motivated charges of sodomy and corruption after clashing with Mahathir over his handling of the Asian financial crisis that battered Malaysia.
Many saw the events as a premature power play that failed badly for Anwar, who critics say is still motivated by intense personal ambition. However, his arrest sparked street protests calling for "reformasi", or reform, that still resonate today, especially for a younger generation eager for change.
Reporting by Siva Sithraputhran; Editing by Stuart Grudgings and Ron Popeski