In December, Foster-Bell talked about being gay in an interview with TVNZ's Q&A programme, saying he wanted to speak up after comments by Brian Tamaki, being particularly concerned for young gay people growing up in provincial New Zealand.
"It's actually throwing petrol on a fire when you send out a message that gay people are very similar to murderers, they're sinners, and they're creating natural disasters. You and I can dismiss that as intelligent adults as just being ludicrous, but for those kids, that's actually a really hurtful thing at an already difficult time in their life," he told the television programme.
Before entering politics Foster-Bell was a diplomat, including postings to Saudi Arabia and Iran.
Last year Foster-Bell faced accusations of poor management after reportedly having 12 staff leave over a period of three years. His relatively high travel and accommodation bill also came under scrutiny.