The search for missing soldier Michael Ross on Lake Moawhango will continue over the weekend, with police, the Navy and Coastguard all taking part.
Private Ross fell overboard from an inflatable boat while on a training exercise on the lake near Waiouru on Tuesday evening.
The Navy dive squad today used sonar equipment in their search of the lake but without success, Inspector Steve Mastrovich said.
The Wanganui Coastguard also provided a boat, which was out on the water today, searching in the cold and rainy conditions.
"We will continue searching over the weekend until we locate Private Ross and are able to return him to his family and loved ones,'' Mr Mastrovich said.
Private Ross, from Kaitaia, was a rifleman based at Linton who enlisted in the army in 2009.
The Defence Force said he was an experienced soldier who served in Timor Leste last year.