An advisor to the former Howard government has criticised Ireland during a discussion about the nation’s successful vote for same-sex marriage.

Grahame Morris, who advised John Howard and has led election campaigns for the Coalition, appeared on Sky News on Monday to say the Irish couldn’t vocalise the difference between ‘tree’ and ‘three’, had a mutant lawn weed – the clover – as a national symbol, and the nation couldn’t grow potatoes.

The Irish recently voted in favour of same-sex marriage, which Mr Morris was discussing.

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The comments raise some of the most troubling times in Irish history, when about a quarter of the population either left the country or died from hunger due to a disease outbreak that wiped out its potato crop in the late 1800s.

His reference to a mutant lawn weed appears to be about the four-leaf clover, but in fact the Irish symbol, the shamrock, is a regular three-leaf clover.

Mr Morris is the federal director of the Barton Deakin lobbying firm, and was appearing on Sky News as a right-wing voice in a panel discussion with the Labor strategist Bruce Hawker.

Prime Minister Tony Abbott has also made controversial comments about Ireland.

“I can’t be there to share a Guinness or two or maybe even three,” Mr Abbott said this year on St Patrick’s Day, while wearing a green tie.

Irish leader Taoiseach Enda Kenny rejected the comments.

“I’ve heard the Prime Minister’s comments. He made them. I don’t agree with that,” he said.

“I think that it is perfectly in order for so many Irish people in Australia to have an enjoyable celebration of St Patrick’s Day and St Patrick’s week, and to do so in a thoroughly responsible fashion.

“There has been a long-term view of a stage Irish perception. I reject that.”

The speech was similar to one he gave in 2014 where he used the same line about Guinness. He was also forced to apologise to the Irish Embassy in 2011 for a disrespectful joke he used as opposition leader.

Mr Abbott said the Gillard government was “a bit like the Irishman who lost 10 pounds betting on the Grand National and then lost 20 pounds on the action replay”.