Waratahs five-eighth Lachlan Mackay announced his decision to join the Western Force and Clyde Rathbone could be next as the Perth Super 14 rugby franchise begins to take shape.

While Mackay was putting the finishing touches on a three-year deal, Rathbone was jetting into Perth for a first-hand look at the club which is showing signs of being a genuine force in its Super 14 debut next year.

Rugby WA still has a long way to go as it scours the country and abroad for the 33 players it needs for its debut in the expanded competition, but it's first three major signings make for an impressive start.

Mackay, a former Australian under 21 captain, joins Queensland second-rower Nathan Sharpe and Waratahs hooker Brendan Cannon as signings for the new club.

Rathbone will spend the next three days in Perth learning more about the city and the club before making his decision to stay in Canberra or join Perth or NSW.

Brumbies halfback Matt Henjak flies into Perth on Thursday for a similar reconnaissance mission.

For Mackay, the opportunity to be a foundation member of the Force was too difficult to resist.

"I have agonised over the decision - especially since our win over the Brumbies last Saturday," he said.

"But, in the end, the opportunity to be part of helping to build a brand new rugby team influenced my decision.

"It won't be easy leaving the Waratahs, especially when we're in with a big show of winning the Super 12, but I am comfortable with my reasons for making the switch".

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