Under the PR system, the relationship between political parties would be significantly different from the FPTP system. The PR system would encourage each community to form its own nation-wide party, as parties would receive seats in proportion to their vote share. This would lead to a multi-party system where smaller parties like PMK, BJP, and DMDK (which got 0 seats under FPTP despite winning votes) would gain representation.

Unlike the FPTP system that normally results in a two-party system and makes it difficult for new or third parties to enter competition, the PR system would allow more parties to share power. This would likely result in coalition governments becoming the norm, as no single party would easily get a majority. Parties would need to work together and form alliances to govern, changing the nature of political competition from winner-takes-all to power-sharing arrangements.