Director of Rugby Dai Young has been busy adding to his squad ahead of the new campaign and the signing of Shields, who played for England over the summer, from the Hurricanes will bolster the back-row, while the Highlanders' Sopoaga has played at fly-half for the All Blacks.
Both are previous Super Rugby champions and join an already talented squad at the Ricoh Arena.
26-year-old Bassett is backing them both to have a big impact, with the top four again his side's primary goal.
He said: "Brad Shields playing for England has been absolutely amazing and we're really excited to get Lima Sopoaga involved - a fly-half that's played for the All Blacks.
"It's going to be really exciting to see what they come and add to the team, but also use their mentality and their environment from playing in Super Rugby to then bring that mentality.
"We had a few bad results at the beginning of last season and probably paid for it a bit later on.
"For us it's about hitting the ground running, getting the results and if we can eventually get to that top four then that would be great."