Just to muddy the waters a little from way down here south of the equator.
Most small airports in NZ that are situated either laterally or vertically clear from controlled airspace have SIDs. These SIDs do not provide any separation from VFR or even any IFR traffic operating in that uncontrolled airspace. IFR traffic will be given traffic information on all other IFR traffic but not necessarily on any VFR traffic (the airfield may be out of radar coverage - most are - and the VFR aircraft won't be on any of the radar or procedural controller's frequencies).
The SIDs have been established to provide safe climbout routes that are clear of terrain obstacles and will position the aircraft so that it may intercept it's cleared route and controlled entry into controlled airspace. It behoves all pilots operating in the vicinity of these uncontrolled airports to communicate and coordinate their movements.
At controlled airports (CTR/C or CRT/D airspace designation) with CTA/C or CTA/D airspace above, the SID issued, in addition to providing climbout terrain clearance, may also provide positive separation from IFR and VFR traffic. The amount of positive separation though depends on the airspace designation. Radar may or may not be available.
Tower controllers throughout NZ have radar screens but they are limited in what they can do with it - it is just a tool that enables them to see approaching and local traffic that is within radar coverage (not all radar coverage is to ground level). Most tower controllers are not approach controllers as this function is done, in the main, from one central air traffic control centre that is in some cases many hundreds of miles from the actual airfield.