Elaine Pearson, deputy Asia director of New York-based Human Rights Watch, said in a statement:
"Once again, elections in Malaysia are grossly unfair to the opposition. Malaysia's ruling coalition is too comfortable with the status quo to allow reforms that would level the playing field.
When opposition leaders and civil society groups critical of the government try to organise rallies, they are blocked at every turn.
Yet the usual excuses about unruly protesters and blocked traffic are never mentioned when the ruling coalition wants to get its supporters out on the streets.
Clouding the fairness of the poll were curbs on the media, with the opposition locked out of state television and radio, as well as irregularities in voter lists and vote counting procedures.
Voters in Malaysia deserve a chance for every vote to count and count equally. Given the vast array of anomalies in the electoral rolls, this looks increasingly unlikely.
Malaysian law and practice allow the ruling coalition to campaign freely but put severe restraints on opposition groups, with police denying them the permits needed for any gathering of four or more people, for example.
The government is using the spectre of ethnic violence to deter public demonstrations and silence its critics."
Sky News report'Dead People' To Vote In Malaysia Poll
According to the New Straits Times, Malaysia's Election Commission has found the names of 8,666 registered voters with birth dates from a century or more ago, including two 128-year-olds.
Dr Anwar says the vote will be flawed and media coverage of the election has been totally unbalanced.
"Do you know that not one report about me in the media, in the government-controlled media or an entire mainstream media in this country," he said.
"There's a complete ban, a blackout, and yet you call it free and fair elections."
Since 1999 The World asked this:
The Front has placed full-page ads in newspapers, many using crudely reworked or faked photos, aimed at showing the opposition in a bad light.
Opposition parties face an uphill challenge against National Front dominance
Stories alleging corruption and sexual impropriety have been widely circulated in the government-controlled press.