It's a special duck that can force a small army of burly contractors with hefty earthmoving equipment and a strict project timetable across a major Dunedin stream and keep them there for a month.

But Claudia the duck, heavy with egg and in need of a nesting site, did just that.

Claudia decided to settle in to produce her ducklings this year in the middle of where Downer workers were busy on the $3.5 million Otago Regional Council Leith flood protection scheme.

Watch: Family of ducks get police escort across road


Site engineer Scott Reid - through an ORC communications spokeswoman - said Claudia's nest was found early last month by Mark Green, a man he described as ''a very observant member of the construction crew''.

Mr Green was undertaking some cleaning on the right bank wall extension of the waterway, 5m upstream from the Leith footbridge, when he discovered the expectant bird.

''After consultation with Fish and Game and discovering it would take about 30 days for the eggs to hatch, it was decided that work on this section of the contract would be put on hold to allow nature to take its course,'' Mr Reid said.

Claudia took advantage of the reprieve and last week produced nine ducklings.

The family was last seen ''playing in the weirs downstream of the work site''.