Emergency services were last night searching for a man missing in the Waikato River, after he entered the river from a natural hot pools in Taupo.

Police were alerted to the incident last night about 9pm after other swimmers at Spa Park hot pools saw him disappear about 200m downstream.

It appears the man had attempted to swim across the river but didn't get to the river bank.

The natural hot pools is a popular spot for Taupo locals and visitors and is where the Otumuheke Stream flows into the Waikato River.

Police, the Greenlea Rescue Helicopter, Coastguard Lake Taupo and Land Search and Rescue volunteers all took part in the search.

The Police National Dive Squad will join the search this morning.

Senior Constable Barry Shepherd said they would be grateful for any information that could help to identify him.

If he had swum successfully down the river from Spa Park to Reids Farm, Police are urging him to call.

Anyone with information should call 111 and ask for Police.

Police said there were about 20 people at Spa Park last night when the man went missing.