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On Sunday, Liberal senator Zed Seselja and independent senator Jacqui Lambie called for a referendum to be held in Australia, arguing the people should have a say.

Last week, independent senator Glenn Lazarus also promoted the idea, inexplicably threatening to don a mankini if the vote failed.

However, prime minister Tony Abbott, opposition leader Bill Shorten, and advocacy group Australian Marriage Equality (AME) have all rejected a referendum. Here's why: