Under the Block Vote, when voters cast all their votes for the candidates of a single party, which is often the case, the system tends to exaggerate all the disadvantages of FPTP, in particular its disproportionality. In Mauritius in 1982 and 1995, for example, the former opposition won every seat in the legislature with only sixty-four and sixty-five percent of the vote, respectively. This created severe difficulties for the effective functioning of a parliamentary system based on concepts of government and opposition.

A critical flaw of the Party Block is the production of 'super-majoritarian' results, where one party can win almost all of the seats with a simple majority of the votes. In the Singaporean elections of 1991, for example, a sixty-one percent vote for the ruling People's Action Party gave it ninety-five percent of all seats in parliament.