His one-year deal in Sydney's west will add another chapter to his already impressive T20 tale and is a massive coup for the Thunder, who desperately needed to improve their pace-bowling stocks in their bid to make a swift BBL finals return.

Giving up his New Zealand contract means the left-arm speedster has all but given away his international career in pursuit of the T20 game.

Before starting with the Thunder he'll play for Durban in South Africa's inaugural T20 Global League. He's also plied his trade in England, played for the St Lucia Stars in the Caribbean league with Shane Watson and was the leading international wicket-taker in this year's Indian Premier League for the Mumbai Indians, where he played alongside long-time idol Mitchell Johnson.

McClenaghan admits the decision to forego his New Zealand central contract was one of the toughest he's had to make, but he's delighted with the path he's chosen.

"Anyone who is playing cricket for their country holds on to aspirations of playing Test cricket," McClenaghan said.

"It just got to a point where there was probably going to be limited opportunity first and foremost to prove my case to play Test cricket with the timing of all our one-day cricket, it clashed with all our first-class stuff.

"I got to a realisation that I probably wasn't going to have the time to prove myself and force my way into that side.

"It's probably been a blessing that I haven't played too much first-class cricket over the last three or four years, because it's just been non-stop white ball and I think the key – particularly in white ball cricket and T20 cricket now – is consistency of playing and performing your skills because it's very hard to change across formats."

McClenaghan has one of the best strike rates in T20 cricket and has claimed 54 wickets in his three years in the IPL.

He took 19 scalps this season in helping the Mumbai Indians to the IPL title and has 112 wickets for New Zealand at international level across the 50-over and T20 formats.

The 31-year-old has long been an admirer of Johnson before earning the chance to play alongside him, so much so that he modelled his bowling action on the fiery West Australian in the early stages of his career.

"I remember changing my action to bowl like Mitch. I made my first-class debut with Mitch's action and it's kind of evolved from there," McClenaghan said.

"I got my first first-class wicket off a wide full toss to point, I probably emulated him probably a little too well. At that point I realised I needed to change.

"To meet him at Mumbai was bloody awesome. I was just hoping he was going to be a good bloke, he's an absolute gem.

"We got on like a house on fire."

Meanwhile, Alex Blackwell has penned a two-year contract extension at the Thunder and will captain the side again this season.

The Thunder are hopeful of luring internationals Harmanpreet Kaur and Stafanie Taylor back to Sydney and both players are believed to be close to signing.

"When we unfortunately got knocked out of the World Cup semi-final by Harmanpreet and I congratulated her on her most incredible innings ... she said something along the lines of don't you worry I'll do the same for Thunder," Blackwell said.

"That gives me great confidence and I hope she does, because that was the best innings I've ever seen."