Managing director of Kai Point Coal and other local companies, Mr Cross was happy to support "a facility of this calibre", driven by locals to ensure the district continued to be a great place to live and work.
"Facilities like this are extremely important for the continued success of our district."
Clutha recreation centre chairman Jeff Seymour said he was "over the moon" with Mr Cross' donation.
"We have been blown away with the generosity of this community," he said.
The committee also confirmed Dynapoint rubber and polyurethane surfacing would be used for the centre's floors despite needing $200,000 more to open the centre "debt free".
An open day will be held this Saturday and Sunday from 11am to 1pm.
Balclutha community co-ordinator Irene Mosley said the open day would be a chance to see the recreation centre's progress. The site has previously been closed to the public.
The fundraising campaign for the centre was launched at the end of November with a target of $850,000. About $650,000 has been raised through gifts and pledges. About $10,000 was raised at the Highlanders vs Blues game at the end of January.
