Yorkshire have signed New Zealand batsman Kane Williamson to help bolster their batting resources as they attempt to secure the LV= County Championship title in their 150th season.

Concerned by the growing number of international calls on their squad, with Gary Ballance, Alex Lees and Liam Plunkett playing for England Lions against Australia later this week in Northampton, while Tim Bresnan, Joe Root and Jonny Bairstow have helped England retain the Ashes, they have signed the 23-year-old batsman for the final five matches of the championship season.

Ballance has also been selected for the Lions squad to face Bangladesh A next week, so Williamson will replace him for the championship match at Trent Bridge against Nottinghamshire, which starts next Wednesday, having toured England earlier this summer as part of New Zealand’s squad.

“Once we knew that Gary was unavailable because of his international call-up, we made a conscious effort to bring in a proven international batsman to help bolster the squad,” admitted Jason Gillespie, Yorkshire’s head coach.

“The decision was made in consultation with Martyn Moxon and Andrew Gale, and Michael Vaughan, representing the Board on cricketing matters, also played a pivotal role in bringing in Kane. It is the right thing to do and he is a quality player with a proven first-class record.”

Ballance’s importance to Yorkshire’s line-up was underlined in his final innings before joining up with the Lions this week, hitting his highest one-day score for the county to help them secure a 32-runs Yorkshire Bank 40 victory over the Unicorns yesterday.

He hit 139 off 113 balls, including 15 fours and three sixes, to help Yorkshire register 266-6, their highest total of a disappointing YB40 campaign that has included only three wins from their first ten matches.

His innings was crucial to Yorkshire’s triumph against the bottom side after they were put into bat and slipped to 16-2, but Ballance forged a 134-run partnership spanning 23 overs with Alex Lees, who fell lbw to former Durham all-rounder Garry Park for 63.

Ballance also combined with Liam Plunkett in a destructive partnership of 76 off 35 balls before holing out to long off with two balls of the innings remaining.

By then he had already taken 24 off the 38th over of the innings from seamer Dominic Reed.

The Unicorns put up a spirited reply with former Derbyshire batsman Matt Lineker hitting 107 off 105 balls, including nine fours and a six, but lost six for 32 to be dismissed for 234 with Jack Leaning’s off-spin claiming 5-22.