Officers from the Yorkshire and Humberside Underwater Search and Marine Unit are making preparations for the dives tomorrow and Friday.
The 74-year-old was diving a wreck with a group from the diveboat Francis Anne about two miles off the Scarborough coast when he failed to surface on Sunday evening.
Officers tweeted that they would only be able to spend a short time on the bottom because of the depth involved - 46m.
They said they would also suffer nitrogen narcosis, a condition which can affect judgement and co-ordination and cause giddiness - or at the other end of the scale, extreme anxiety.
North Yorkshire Police said they were supporting the missing diver’s family and keeping them up to date with the search plans.
The diver, from Scarborough, was reported missing at 6.55pm on Sunday.