Updated 5.18pm: Nelson residents wanting to try out a 300 metre water slide may be out of luck.

Nelson City Council has rejected a request by organisers of the event called Monster Slide to close Collingwood and Bronte streets putting the February second event in doubt.

Council Chief Executive Clare Hadley says it was rejected because of concerned residents.

"We've had a number of residents register their objections to the proposal, and they raised a number of issues that we thought were valid, and that could not be easily overcome."

She says they haven't shut the door on the event completely.

"The Council has asked the organiser to if he would like to work with them to see if any other suitable site can be identified."