There have been surges in the water on the main beach at Akaroa on Banks Peninsula.
Many people were evacuated from motels and homes near the beach.
Dramatic water movement was reported in Lyttelton Harbour.
Chris Hutching of Christchurch said from Diamond Harbour that the tide receeded almost as far as Quail Island. Dirty water then came in at a rate of about six knots.
Residents told him that old jetties they had never seen before, were revealed.
Some boats moored at the Lyttelton marina received minor damage.
But the Regional Harbourmasters Office spokesperson, Evan Walker, is warning boaties not to go to the marina to check their vessels or to go sailing on Sunday, because of the likelihood of surges.
Mr Walker says the owners of the damaged boats have been contacted.
However, Civil Defence in Christchurch says latest information now suggests evacuations are not required for the Christchurch or Banks Peninsula areas.
But it is still a good idea to remain prepared in case the situation changes.
Civil Defence says the waves may continue to be larger than usual for several more hours.
Therefore people are asked to stay away from coastal areas, including exposed foreshores, estuaries and river mouths.
Lower south OK
No significant rise in sea levels has been detected so far in southern New Zealand.
However, Civil Defence still advises people to stay clear of coastal areas until further notice.
Dunedin Civil Defence manager Neil Brown believes there is no risk of a major civil emergency occurring in Dunedin.
However, Otago Regional Council warns unusual tidal patterns are possible over the next 12 hours.
Police officers are patrolling Dunedin beaches and advising people to stay well away from the coast.
Waitaki District Council says there is a very low tide in Oamaru Harbour.
Operations manager Eric Spittal said about 60 campers at the Hampden camping ground have moved to safety as a precaution.
In Southland, boaties were contacted through marine radio about the tsunami risk.
