Fine Gael had decided to re-admit three Senators who lost the party whip following their participation in the controversial Oireachtas Golf Society event in Cliften last August.
During a meeting of the parliamentary party Tánaiste Leo Varadkar proposed a motion that Senators Jerry Buttimer, John Cummins and Paddy Burke be readmitted.
The event was criticised because participants breached Covid-19 rules which prohibited large gatherings.
The Fine Gael leader said: "They all acknowledged that what happened at the Oireachtas Golf event should not have happened, apologised and took responsibility immediately.
"They have been out of the parliamentary party for five months and it's time for them to get back to working with us across the whole range of Oireachtas work, including relating to battling against Covid."
The motion was agreed unanimously.
Mr Varadkar told the parliamentary party meeting that the sharp rise in positive Covid-19 cases was twice as bad as the worst case projections.
He said the increase arose from a combination of factors including house gatherings, hospitality settings, the new variant of the virus, travelling around the country, mixing of homes over Christmas, international travel with people not isolating for 14 days and illegal gatherings such as shebeens.
The Fine Gael leader said everyone needed to continue to work to get community transmission down.
Mr Varadkar said the situation in hospitals was going to be very difficult for the next few weeks due to the high case numbers.
Between 50,000 and 55,000 will be vaccinated this week and it is hoped everyone in a nursing home or long-term residential care centre will be vaccinated by Sunday week, he added.