The NSW Innovation Minister, Matt Kean, has apologised for the "spectacular" end to his relationship after his girlfriend, a media adviser to Malcolm Turnbull, shared explicit texts Mr Kean sent to the Miranda MP, Eleni Petinos.

Mr Kean issued a statement late on Thursday night after his girlfriend, Caitlin Keage, shared screenshots of text messages between Mr Kean and Ms Petinos on Instagram.

"I was in Adelaide trusting my partner not to play up. But alas, here we are. Another minister getting away with his predatory behaviour," Ms Keage's Instagram post said.

Under the screenshot of the message she also wrote: "When your boyfriend cheats on you when you're away with family @matt_keanmp."