The world is John Key's oyster in terms of his future career, with the Prime Minister likely to be inundated with job offers, according to a recruitment expert.

Following the shock resignation this afternoon, Key has said he was planning to spend time with his family but recruitment firm Sheffield executive director Ian Taylor said Key would have something up his sleeve.

"I'm sure he'll have some things at the back of his mind, but he'll be wanting to take some time and reflect," Taylor said.

"It's good timing for him so he's got the summer and autumn to think about things, but he will have options at every level."

Taylor said Key's former career in the financial services industry and as finance spokesperson gave him a broad skillset that a number of companies would consider attractive. Governance was a likely option however.

"He would have a vast array of options open to him from governance in boards and chairmanships, not only locally but regionally and internationally, so that's one possibility," Taylor said.

"The other interesting thing is observing how popular and capable he is on the international stage, so it would seem logical that that's one of his options as well to continue to work internationally in political NGO not-for-profit organisations or ones focused on international finance."

Key's best asset for a future career is likely to be his extensive networks both in New Zealand and internationally. Taylor highlighted Key's friendship with Obama as an example of his ability to develop strong business and political relationships which would be invaluable to whatever business venture he decided to pursue.

"His network must be absolutely enormous not only in terms of who he can call up and have a conversation with, but also that he is so well respected and effective as a relationship broker and facilitator in tough times and across tough issues," Taylor said.

According to Taylor, the difficulty would be in choosing a career or future options that also left time for his family and other hobbies. Either way he said Key was likely to be fielding offers for the coming few months.