Wesfarmers already owns Bunnings - one of Australia’s largest suppliers of outdoor living and DIY products.
The 265 UK Homebase sites, including one just off Wheatley Hall Road, will be rebranded under the Bunnings banner over the next three to five years.
Wesfarmers said it would spend a further £500m on upgrading the UK stores.
Following the announcement, Usdaw, the shopworkers trade union, is seeking urgent talks with Westfarmers’ bosses in a bid to establish a ‘constructive working relationship’.
Dave Gill, Usdaw’s national officer, said: “We have a longstanding commitment to providing trade union representation for Homebase staff and have maintained relationships with successive owners of the business.
“We are looking forward to working closely with the new owners and I am seeking to meet them as soon as possible.
“We understand they are looking to invest in the Homebase business, which is welcome after the restructuring and job losses at the end of 2014.
“In the meantime, I am writing to all our members working in Homebase to reassure them that Usdaw will provide support, advice and representation throughout the period of transition.”
Usdaw has more than 440, 000 members nationwide.