Safety concerns about the design of the ramp and its surrounds heightened in summer because of the fluctuating level of Lake Roxburgh.
Contact Energy was given permission in 2009 to raise the lake level by up to 60cm to generate more electricity.
Boating club president Brent Wilson told the Otago Daily Times in January the fluctuating lake level meant a border of large rocks around the ramp was being undermined and was unstable.
The rocks were often partly or fully submerged, creating a hazard for boat users launching their craft or taking their boats out.
Several agencies and interest groups recently joined forces to upgrade the ramp, which is the only official access boat users have in Alexandra to the Clutha River and Lake Roxburgh.
Lake Dunstan harbourmaster Shayne Hitchcock said the temporary mooring area was improved and a retaining wall was built along one side of the boat ramp.
The large rocks closest to the water were removed.
More beach area was created and willow trees near the site were thinned out.
Mr Hitchcock said the work involved the co-operation of Contact, Linz, the Otago Regional Council, the Clutha Management Committee and the Central Otago District Council.
A team of volunteers spent two days on the project, which cost about $10,000.
"It'll be safer now getting people on and off vessels, now one side of the ramp has been built up.
"We've also opened up access to the former rowing club beach along the river, which had become overgrown with trees."
Mr Wilson praised those who worked on the project.
"This is a classic example of what should happen - how interest groups and the local council can work well together."
Club members believed the work had improved the ramp considerably and made it more user-friendly, he said.
"It's opened the area up, which should ease the congestion at peak times, as there will be more beach to use, and the upgrade has meant there is less risk of accidents."
