There is mounting pressure on Tasmanian senator Jacqui Lambie to apologise to two Vietnam veterans from the New South Wales central coast after appearing to refer to them on social media as "the sort of men who kiss the PM's arse".

Key points: Jacqui Lambie posted photo to Facebook with offensive comments

Jacqui Lambie posted photo to Facebook with offensive comments Comments said the Vietnam veterans in photo "kiss PM's arse"

Comments said the Vietnam veterans in photo "kiss PM's arse" Local MPs on NSW central coast outraged

Local MPs on NSW central coast outraged Pressure mounting on Senator Lambie to apologise

The pair was photographed with Prime Minister Tony Abbott during a visit to Gosford last month, where they discussed concerns about the Department of Veterans Affairs overpaying veterans.

The image appearing on Senator Lambie's Facebook page with the comment: "These are the sort of men who kiss the PM's arse and say thank you for nothing."

"These kind of men say it is OK to treat a veteran like a piece of shit," the comment said.

The post has since been removed.

The Vietnam Vets Central Coast sub-branch president Robert Purcell said he was deeply offended by the remarks and Senator Lambie should apologise.

"I just cannot believe that a senator of Australia could look at a photo and just make up a story about it," he said.

"It seems inconceivable that someone would want to do that, especially in her position."

Local MPs on both sides of politics also expressed outrage.

Robertson Liberal MP Lucy Wicks, who organised the meeting between Mr Abbott and the veterans, said she was "shocked and appalled" by the comments.

Dobell Liberal MP Karen McNamara said she was disgusted.

Veterans 'irate or completely overwhelmed by despair'

Labor senator Deb O'Neill said the comments were inappropriate but reflected growing frustration with the Government and its "dysfunctional" treatment of veterans.

"There is heat everywhere in this," she said.

"Veterans are either irate or completely overwhelmed by despair.

"They are so, so distressed by the treatment they are getting from the department at the moment.

"This is an ongoing sore that has upset everybody involved in it.

"Of course that's no excuse for the sort of language that Senator Lambie used."

Ms Wicks would not be drawn on concerns raised about the department.

"This is not an issue of politics," she said.

"This is an issue about outstanding community representatives on the central coast."

The ABC has attempted to contact Senator Lambie for comment.