The Catholic provider has made a major deal, purchasing Belroses four aged care homes at Joondalup, Kelmscott, Maddington and Rockingham to add to its existing home in Wembley.
While the price remains confidential, the move will see MercyCares number of beds boosted from 113 to 367 and their staff from 700 to over 1,000.
The 40-year-old Wembley home is currently under refurbishment and MercyCare has announced plans to expand facilities and services at the four new sites too, lifting their bed numbers to 500.
The deal is expected to settle in late September.
