It will be carried out on the runway, taxiways and apron to keep the airport operational through winter.
Contractor Amco Giffin will work only at night to minimise flight disruption.
The States of Alderney said it highlighted the need for future-proofing the site.
The original plans for full runway rehabilitation would have meant repairs on the existing runway would not be needed, but the plans were postponed earlier this year while all options were considered.
The island’s Policy and Finance Committee has said at the very least, option C+, which would extend the runway to the west, should be put to tender.
‘We are clear that an extended, modernised and widened runway makes the most sense and would future-proof the island’s air infrastructure,’ said P&F chairman Bill Abel.
‘We have heard some seriously inflated figures put forward in some quarters, and to Alderney this option, based on irresponsible guesswork, would be a gross injustice to Alderney and its community now and in the future.’
He said option C+ would only be considered the best option if project tenders in both islands suggested it would provide the best value in the mid- to long–term.
‘The States of Alderney sees a host of very significant advantages if the longer runway option does progress,’ said Mr Abel.
A longer runway would allow ATR aircraft to use the airport, providing an additional 20,000 passenger seats a year, as well as a dedicated medevac service and access for larger private aircraft.
States’ Trading & Advisory Board president Deputy Peter Roffey said the current runway was ‘on life support’.
‘What we really want is to build a new runway.’
He said however that maintenance work must be completed to ensure connectivity.
‘We can’t allow Alderney to be cut off from the rest of the world.’