Council chief executive Adam Feeley said altering the fast slide - one of two at the $18 million Alpine Aqualand - was under way and design work was planned for completion in January.
Physical work would begin early February with ''commissioning and trialling'' of the fast slide expected in late February or early March.
In November the Otago Daily Times revealed a dispute over the safety of the fast hydroslide, closed in June 2009, had been resolved through a confidential arbitration process.
At that time, Queenstown Lakes Mayor Vanessa van Uden said the slide would be modified to cater to a ''wider demographic of users''. Work was to have started in November and the slide reopened this month, in time for the school holidays.
However, no physical works have been evident at the Queenstown Events Centre since that announcement.
The council was approached last month for comment about the issue and this week chief executive Adam Feeley said engineering design issues had proven ''more complex than first anticipated''.
''We cannot in any way compromise safety issues and, therefore, these matters will be addressed before reopening.''
The ODT previously reported the work would include the modification of a ''portion'' of the exterior of Alpine Aqualand and the extension of the slide's total length.
The arbitration process had been ongoing since 2009 between the council, on behalf of Lakes Leisure Ltd, Naylor Love, the building company given the contract to construct the hydroslide and Timaru manufacturer Aeromarine Industries Ltd, a subcontractor responsible for the design and building of the two hydroslides.
The fast slide was closed briefly in December 2008 after 69 patrons reported minor injuries, the majority caused by users breaking safety rules.
After intermittent closures, it ceased operating in June 2009 after a woman suffered a concussion and shoulder injury while using it.
The Department of Labour investigated the woman's complaint, but decided in November 2009 not to prosecute. Following a request under the Local Government Official Information and Meetings Act 1997, last month the council released figures to the ODT showing it had spent $137,348 on the matter between late 2009 and September 30 this year.
Of that, $105,492 was spent on legal and arbitration costs, which peaked in the 2011-12 financial year, when $52,115 was spent. The remaining $31,856 was attributed to staff costs. In 2009, the ODT quoted project manager Ken Gousmett saying the slide would be fixed at ''no cost to the public, the council or Alpine Aqualand'' as it was under a full 12-month warranty. However, when asked last month, Mr Gousmett said the council could not confirm that was still the case.
''The question goes to the outcome of the arbitration which is subject to confidentiality.''
