Hmm that sounds a little bit like an issue I had recently with power steering. Check the powersteering tank and see if it's down on the cold min? If so, have a look for a leak, may be able to spot the drips on the undertray if you can get some light and an angle to look down inside the engine bay?
In my case, these high pressure pipes that sit on the passenger side had seen some weather and developed an ever so gradual leak (all greek to me, but Steve gave me a gander at the goosed part). It's a part nissan have recalled & uprated, and sponsored to keep the price down thankfully, and Falcon sorted it all out for me.