Growing concern in Birkenhead as a large slip inches closer to nearby buildings.

The slip at the Rawene car park widened on Tuesday and is now around 10 metres from a number of properties.

Business owner Brad Boult said residents had been assured the ground was stable by the Council several days ago, before the slip gave way even further this week.

"Long-term the council needs to commit to reinstating the carparks fully so that the business community has that resource".

Boult said the Council's been sending out mixed messages about the slip, and residents are confused.

"They did send out an email a couple days ago saying that everything was stable and then all of a sudden it's not stable. So maybe the need to reassess things".

The slip has swallowed at least 25 car park spaces and has caused machinery to fall into the hole.