AccessDeniedException: User is not authorized to perform: lambda:InvokeFunction

I'm trying to invoke a lambda function from node.

var aws = require('aws-sdk');var lambda = new aws.Lambda({    accessKeyId: 'id',    secretAccessKey: 'key',    region: 'us-west-2'});lambda.invoke({    FunctionName: 'test1',    Payload: JSON.stringify({        key1: 'Arjun',        key2: 'kom',        key3: 'ath'    })}, function(err, data) {    if (err) console.log(err, err.stack);    else     console.log(data);});

The keys are for an IAM user. The user has AWSLambdaExecute and AWSLambdaBasicExecutionRole policies attached.

I get a permission error:AccessDeniedException: User: arn:aws:iam::1221321312:user/cli is not authorized to perform: lambda:InvokeFunction on resource: arn:aws:lambda:us-west-2:1221321312:function:test1

I read the docs and several blogs, but I'm unable to authorise this user to invoke the lambda function. How do get this user to invoke lambda?