MPs have been urged to vote down Prime Minister Najib Abdul Razak's budget next month amid his unresolved scandals and concerns the budget may be tailored to prolong his political survival.

The call was made by Demi Malaysia, a loose coalition of activists, which in August organised the #TangkapNajib rally in Kuala Lumpur that saw more than 20 people arrested by the police.

To drive home its message, Demi Malaysia said it will organise a protest at the Parliament entrance on Oct 23, when Najib, who is also finance minister, is to table the Budget 2016.

"We strongly fear with the passing of the upcoming budget, more resources and funds will be misused to buy the prime minister time, or buy his way out, at the expense of taxpayers.

"We demand the prime minister's urgent resignation, and urge all 221 other members of Parliament to vote against a budget that is hugely compromised to serve one man's interest," it said in a statement today.

The coalition noted the huge sum of money in Najib's personal bank accounts, which his supporters claim to be a donation, has yet to be properly explained on top of claims of irregularities in 1MDB's US$11 billion debt.

It further noted that there were several efforts to scuttle investigations into the matter, including the replacement of the attorney-general, the transfer of anti-graft investigators, the suspension of critical newspapers and the arrest of several individuals who took up the matter.

"These have resulted in a very negative impact on Malaysia as a whole.

"The country's economy is receiving backlash, the Ringgit currently sits at RM4.44 per US dollar, investors are losing confidence and the country's reputation is at stake.

"None of the above actions is acceptable in any matured democracy. The prime minister has failed to respond to these criticisms in a dignified manner," it said.