"It is with a heavy heart and great sadness that I announce my intention to resign from Parliament," Mr Gilmore said in a statement.
"After taking counsel from colleagues and family in recent days, I have decided that to stay on in Parliament would only serve to cause my loved ones more upset, and cause me undeserved further stress."
Mr Gilmore said media scrutiny in recent days since reports of his night out in Hanmer Springs where he was abusive to a waiter had "put me and those who are important to me under immense pressure with an attempt to discredit me".
"I have made mistakes. I am human. But the attacks on my integrity have started taking a toll on those around me and this is unfair on them."
Mr Gilmore said he'd advised the National Party's whips of his decision.
"I also want to make clear my support for the National Party and Prime Minister John Key remains unwavering."
Mr Gilmore said that he is extremely honoured to have been a member of the New Zealand Parliament and has always worked to make the lives of the people of Christchurch better.
Mr Gilmore wished to express gratitude to his family and friends who have shown support and understanding over the past two weeks.
"Finally, I want to apologise once again to all those people who I've let down with my behaviour. I'm determined to learn from those lessons as I continue my life with more grace and humility.
"I will seek to make a final statement in Parliament on Tuesday."
