We report the detection of the SiO ( J = 2 \to 1 ) transition from the massive cold dense core G333.125 - 0.562 .
The core remains undetected at wavelengths shorter than 70- \mu m and has compact 1.2-mm dust continuum .
The SiO emission is localised to the core .
The observations are part of a continuing multi-molecular line survey of the giant molecular cloud G333 .
Other detected molecules in the core include ^ { 13 } CO , C ^ { 18 } O , CS , HCO ^ { + } , HCN , HNC , CH _ { 3 } OH , N _ { 2 } H ^ { + } , SO , HC _ { 3 } N , NH _ { 3 } , and some of their isotopes .
In addition , from NH _ { 3 } ( 1,1 ) and ( 2,2 ) inversion lines , we obtain a temperature of 13 K. From fitting to the spectral energy distribution we obtain a colour temperature of 18 K and a gas mass of 2 \times 10 ^ { 3 } M _ { \scriptsize \sun } .
We have also detected a 22-GHz water maser in the core , together with methanol maser emission , suggesting the core will host massive star formation .
We hypothesise that the SiO emission arises from shocks associated with an outflow in the cold core .