Sir Jeffrey Donaldson said Covid-19 is "no joking matter" when asked about Sammy Wilson's "ding dong" tweet about the Omicron variant.
The DUP leader addressed the controversy during a visit to the Shankill Road on Thursday afternoon.
He said he will be speaking to his party colleagues to follow public health advice and encourage others to do so.
Three DUP MPs this week voted in the House of Commons against mandatory mask wearing indoors in England.
Sammy Wilson has also been criticised for describing the new Omicron variant as mild.
Sir Jeffrey was asked about a tweet by Sammy Wilson which read: “Ding dong merrily on high will be replaced this Christmas by ping-dong miserably we sigh. I will vote against new restrictions in Parliament today. They are not proportionate to deal with the spread of the mild Omicron variant.”
He responded: “Covid is no joking matter, people have died from Covid, that is clear and I think it is incumbent upon all public representatives to support public health messaging to ensure that we all take the steps that are necessary to protect ourselves and each other, that we get vaccinated, that we get our booster jabs.
“All of this is essential to ease the pressure on the health service this winter and ensure that we get through this winter without lockdowns, without people being out of work, with our schools remaining open.
“This is crucially important and I am clear as leader of the DUP, we support the public health guidance, we want people to follow that public health guidance, we want people to get their vaccinations so that we can all work together to get through this and to see Northern Ireland to the other side of this winter in a strong place with people at work, people at school and people healthy and well.”
We encourage people to wear face coverings. I have been in meetings today, I have been wearing my face covering in all of those meetings, and when I engage with others, we encourage people to go and have their vaccination, get their booster,” he said.
“It’s important that we all play our part, whether that’s in the public messaging or following the public health guidance that is there to help all of us, and that is what we must be doing, and that is what the DUP will be focused on.
“I will be speaking to my colleagues. I am very clear, I want all of my colleagues to follow the guidance, the public health advice and to encourage others to do likewise.”
He said his party “at leadership level is very clear that we want people to adhere to the public health messaging, we want people to follow the advice and the guidance that is being given, and that primarily means getting your Covid vaccination”.
