There is still no sign of a helicopter believed to have crashed into a North Canterbury lake.

The helicopter, with Rangiora pilot Michael Graeme Mehrtens aboard, is believed to have crashed into Lake Sumner, about 140km northwest of Christchurch on Monday.

Four boats, four land teams, the police dive squad and a helicopter searched the area on Tuesday.

A small amount of debris was recovered from the search area and an oil slick was found about 150 metres offshore from Breaksea Bay, on the northern side of the lake, police say.

The search has been suspended for the evening and will resume on Wednesday morning.

Mr Merhtens was the only person aboard the helicopter.

The 35-year-old is an employee of Way To Go Heliservices.

According to his employer's website, Mr Merhtens is primarily an agricultural pilot.

He gained much of his flying experience in Australia.

He has about 3500 hours of helicopter flying time.