Leading Australian Liberal politician Tony Abbott has resigned from his party's front bench, saying he cannot support Australia's emissions trading scheme.
Mr Abbott's move, which brings to five the number of frontbench Liberal resignations this week, came after he and Senator Nick Minchin failed to get opposition leader Malcolm Turnbull to reconsider the party's position on the scheme.
Mr Abbott says he cannot support the scheme without it undergoing further scrutiny.
Mr Minchin has already resigned from his Senate frontbench position, as have fellow senators Eric Abetz and Stephen Parry, though all have offered to stay on until the Senate rises.
Liberal MP Sophie Mirabella has also resigned from the frontbench.