Former Vanuatu cabinet minister, Joe Natuman, says amendments to the Passport Act will allow corrupt politicians to sell passports for personal gain.
Last week parliament amended the Passport Act to allow non ni-Vanuatu diplomats to qualify for diplomatic passports.
As minister of internal affairs last year Mr Natuman ordered the sacking of over 200 diplomats who were not Vanuatu citizens.
He says some were criminals who had damaged Vanuatu's reputation.
Mr Natuman says the government's actions amount to legalised corruption.
"Because government ministers would sell passports to any foreigners for money, to make some money for their campaigns for the coming elections. That is basically what [will] happen. It's a form of legalised corruption."
Last year Mr Natuman spearheaded a government audit inquiry into allegedly fraudulent activity at the Embassy in Beijing.
It uncovered gross mismanagement and corrupt actions, including questions over the issuance of passports.